Send multiplexed audio streams with rtpbin

My Goal
I need to transmit multiple audio streams, each with a distinct SSRC, through a single UDP session by using GStreamer’s rtpbin element and one udpsink. All streams shall be send to a common multicast address and port.

Current approach

  • I link each audio source into a separate request pad on rtpbin:
  • send_rtp_sink_0 for Stream A
  • send_rtp_sink_1 for Stream B
  • I connect what I believed to be the unified multiplexed output pad (send_rtp_src_0) from rtpbin to a single udpsink.

Observed Behavior
Rather than multiplexing all streams onto send_rtp_src_0, rtpbin dynamically creates a separate send_rtp_src_<n> pad for each input sink pad.

Question
Does this design forces me to create one udpsink per stream? Or is there a way to aggregate multiple send_rtp_sink_<n> inputs into a single udpsink (i.e. one RTP session and port pair)?