Hi Bright,
There is already an FP dissector. Instead of taking its configuration from RRC, it reads them from file formats that supply it.
I imagine you'd need to add to the RRC template functions to remember read these values and store them in global tables that may be read by FP (and MAC and RLC). The FP dissector could be changed to also be able to look in these tables for its configuration, and to be made to call a MAC dissector for each TB.
I have no plans to add MAC and RLC, or modify the RRC dissector to build up tables (I have added LTE MAC and RLC but no longer work regularly with UMTS).
Regareds,
Martin