function to check for on request pad collection or not

[Greg Wunder]

The version of GStreamer I am using contains some plugins that have on request sink pads but appear to be different in their use.
Specifically, the element rtpjitterbuffer only allows one sink pad to be created for the sink called "sink_rtcp" & no more can be created after this one as it is not a collection.
In videomixer the sink can be generated many times as I believe a collection is used.
My question is regarding a framework test function for this.
Does GStreamer provide a function to determine if an "on request" pad contains a collection or not?