diff --git a/README.md b/README.md
index 6fd0b972c..872db362e 100644
--- a/README.md
+++ b/README.md
@@ -1631,9 +1631,10 @@ Optionally included keys are:
 * `all`
 
 	Can be set to the string `none` to disable any extra behaviour (which
-	is the default if this key is omitted altogether) or to `all`.
-	Applicable to certain messages only. The behaviour is explained below
-	separately for each affected message.
+	is the default if this key is omitted altogether) or to one of `all`,
+	`offer-answer`, `except-offer-answer` or `flows`.  Applicable to
+	certain messages only. The behaviour is explained below separately for
+	each affected message.
 
 An example of a complete `offer` request dictionary could be (SDP body abbreviated):
 
@@ -2030,6 +2031,13 @@ request`. To select just one media flow for media blocking, in addition to
 selecting a source call participant as above, a destination call participant
 must be specified using the `to-tag` or `to-label`key in the message.
 
+Another possibility to block media for individual media flows is to use one of
+the special `all=` keywords instead of directly specifying a single `to-tag` or
+`to-label`. With `all=offer-answer` all media flows from the given `from-tag`
+that resulted from an offer/answer negotiation are affected. Respectively with
+`all=except-offer-answer` the opposite happens. With `all=flows` all currently
+established media flows are affected regardless or how they were created.
+
 `silence media` and `unsilence media` Messages
 ----------------------------------------------
 
diff --git a/daemon/call_interfaces.c b/daemon/call_interfaces.c
index 21a84a8f3..2f56357f3 100644
--- a/daemon/call_interfaces.c
+++ b/daemon/call_interfaces.c
@@ -1478,6 +1478,17 @@ static void call_ng_main_flags(struct sdp_ng_flags *out, str *key, bencode_item_
 				case CSH_LOOKUP("none"):
 					out->all = ALL_NONE;
 					break;
+				case CSH_LOOKUP("offer-answer"):
+					out->all = ALL_OFFER_ANSWER;
+					break;
+				case CSH_LOOKUP("not-offer-answer"):
+				case CSH_LOOKUP("non-offer-answer"):
+				case CSH_LOOKUP("except-offer-answer"):
+					out->all = ALL_NON_OFFER_ANSWER;
+					break;
+				case CSH_LOOKUP("flows"):
+					out->all = ALL_FLOWS;
+					break;
 				default:
 					ilog(LOG_WARN, "Unknown 'all' flag encountered: '" STR_FORMAT "'",
 							STR_FMT(&s));
@@ -2697,6 +2708,25 @@ static const char *call_block_silence_media(bencode_item_t *input, bool on_off,
 			}
 			g_queue_push_tail(&sinks, sink);
 		}
+		else if (flags.all == ALL_OFFER_ANSWER || flags.all == ALL_NON_OFFER_ANSWER
+				|| flags.all == ALL_FLOWS)
+		{
+			for (GList *l = monologue->subscribers.head; l; l = l->next) {
+				struct call_subscription *cs = l->data;
+				if (flags.all == ALL_OFFER_ANSWER && !cs->attrs.offer_answer)
+					continue;
+				else if (flags.all == ALL_NON_OFFER_ANSWER && cs->attrs.offer_answer)
+					continue;
+				g_queue_push_tail(&sinks, cs->monologue);
+			}
+			if (!sinks.length) {
+				ilog(LOG_WARN, "No eligible subscriptions found for '" STR_FORMAT_M "' "
+						"for media %s",
+						STR_FMT_M(&monologue->tag),
+						lcase_verb);
+				return "No eligible subscriptions found";
+			}
+		}
 		if (sinks.length) {
 			for (GList *l = sinks.head; l; l = l->next) {
 				struct call_monologue *sink = l->data;
diff --git a/include/call_interfaces.h b/include/call_interfaces.h
index 4176c4134..b4edfa5d4 100644
--- a/include/call_interfaces.h
+++ b/include/call_interfaces.h
@@ -79,6 +79,9 @@ struct sdp_ng_flags {
 	enum {
 		ALL_NONE = 0,
 		ALL_ALL,
+		ALL_OFFER_ANSWER,
+		ALL_NON_OFFER_ANSWER,
+		ALL_FLOWS,
 	} all;
 	enum endpoint_learning el_option;
 	enum block_dtmf_mode block_dtmf_mode;
diff --git a/utils/rtpengine-ng-client b/utils/rtpengine-ng-client
index b6dcab8a9..980e6852b 100755
--- a/utils/rtpengine-ng-client
+++ b/utils/rtpengine-ng-client
@@ -69,7 +69,7 @@ GetOptions(
 	'xmlrpc-callback=s'		=> \$options{'xmlrpc-callback'},
 	'always-transcode'		=> \$options{'always transcode'},
 	'metadata=s'			=> \$options{'metadata'},
-	'all'				=> \$options{'all'},
+	'all=s'				=> \$options{'all'},
 	'siprec'			=> \$options{'SIPREC'},
 	'SIPREC'			=> \$options{'SIPREC'},
 	'egress'			=> \$options{'egress'},
@@ -125,7 +125,7 @@ my $cmd = shift(@ARGV) or die;
 
 my %packet = (command => $cmd);
 
-for my $x (split(/,/, 'from-tag,to-tag,call-id,transport protocol,media address,ICE,address family,DTLS,via-branch,media address,ptime,xmlrpc-callback,metadata,address,file,db-id,code,DTLS-fingerprint,ICE-lite,media echo,label,set-label,from-label,to-label,DTMF-security,digit,DTMF-security-trigger,DTMF-security-trigger-end,trigger,trigger-end')) {
+for my $x (split(/,/, 'from-tag,to-tag,call-id,transport protocol,media address,ICE,address family,DTLS,via-branch,media address,ptime,xmlrpc-callback,metadata,address,file,db-id,code,DTLS-fingerprint,ICE-lite,media echo,label,set-label,from-label,to-label,DTMF-security,digit,DTMF-security-trigger,DTMF-security-trigger-end,trigger,trigger-end,all')) {
 	if (defined($options{$x})) {
 		if (!$options{json}) {
 			$packet{$x} = \$options{$x};
@@ -138,7 +138,7 @@ for my $x (split(/,/, 'from-tag,to-tag,call-id,transport protocol,media address,
 for my $x (split(/,/, 'TOS,delete-delay,delay-buffer,volume,frequency,trigger-end-time,trigger-end-digits,DTMF-delay')) {
 	defined($options{$x}) and $packet{$x} = $options{$x};
 }
-for my $x (split(/,/, 'trust address,symmetric,asymmetric,unidirectional,force,strict source,media handover,sip source address,reset,port latching,no rtcp attribute,full rtcp attribute,loop protect,record call,always transcode,all,SIPREC,pad crypto,generate mid,fragment,original sendrecv,symmetric codecs,asymmetric codecs,inject DTMF,detect DTMF,generate RTCP,single codec,no codec renegotiation,pierce NAT,SIP-source-address,allow transcoding,trickle ICE,reject ICE,egress')) {
+for my $x (split(/,/, 'trust address,symmetric,asymmetric,unidirectional,force,strict source,media handover,sip source address,reset,port latching,no rtcp attribute,full rtcp attribute,loop protect,record call,always transcode,SIPREC,pad crypto,generate mid,fragment,original sendrecv,symmetric codecs,asymmetric codecs,inject DTMF,detect DTMF,generate RTCP,single codec,no codec renegotiation,pierce NAT,SIP-source-address,allow transcoding,trickle ICE,reject ICE,egress')) {
 	defined($options{$x}) and push(@{$packet{flags}}, $x);
 }
 for my $x (split(/,/, 'origin,session connection,sdp version,username,session-name,zero-address')) {