Im sorry I seem very ignorant about these topics, but what exactly are talk groups. How are they different than listening to conventional scanned frequecies
Adding to Oslo's comments.
A Trunk System is a combination of shared freqs (TSYS Object) and shared talkgroups (TGRP Objects)
The controller (CC) finds an unused voice frequency (VC) to match the user radio when keyed up with his/her assigned talkgroup (TG) to communicate with another user having same talkgroup. They are able to change the TG to a tac channel with a switch. Dispatch TG is used the most by all users of each agency (Law/Fire) etc.
The idea for your scanner is to place all CC/Alt CC in the TSYS freq section with TGRP's mapped to this TSYS using selected scanlist rather then banks.
A Programming Shortcut is in link below my signature but software is the easiest method.
However, OsloViking might present a very strong argument for manually programming.