Libpri: Any Channel IE?

Does libpri support this:

When doing a call setup, libpri actually sets the bchannel that has to be used for the conversation.

How is it possible to tell the switch that he shall select a channel to use and not the cpe?

The switch then answers in a setup_ack with the channelnumber.

Is such a feature already in libpri? If yes, where?

Thank you!