This is the second time that this has been brought up. It was brought up last year in an article on the same website. While Bryan can talk to CS, rules prohibit Bryan officers from monitoring College Station's system. Surprisingly, the same goes for the SO and Constables.
Now, Blinn does have a TG on the County system, but it has never been used, and Blinn is still using their VHF frequency with iCom radios. As a result, I do not see Blinn going on the system any time soon.
The system as it stands now actually gets out pretty far. I once heard a Brazos County SO deputy check out at the Washington County jail over the radio. Bryan PD was able to pursue a vehicle well north of Hearne and still get out on the system perfectly fine.