Brandmeister use the standard of 3 digit country code and then a 2 digit area. I don't know what c-bridge are but should use the same system or totally different format that do not collide. Each site could have diffent TGs for local use but is often TG9 and then you have to look at the display to see what site it is.
DMR radios have the same TG numbers common for all channels, so if the same TG number are used for different functions on different system then radioamateurs should have huge problems when programming their radios, if they would like to use both systems in one radio.
I have one trunked system setup for amateur use and some sites are Brandmeister and others are not.
You should be able to have both radiosystems in one trunked system in EZ-Scan?
But if not, make one trunked system for Brandmeister and setup it for its own scanlist and with all Radio IDs, and another trunked system for c-Bridge and its own scanlist and TGs. In the Brandmesiter Radio ID list you just add the c-Bridge scanlist. You can share TG and Radio ID across any scanlists you like as it is frequencies that gets scanned and then all TG and Radio ID are just fetched from a lockup table that shouldn't affect scan speed in any way.
I don't really understand what you mean by "there is no way to share radio ids between systems" as that is a feature that makes TRX standout from Uniden scanners. Once you have programmed a TG or a Radio ID you can re-use that in many systems just by adding their scanlist to the record.
/Ubbe