I can't speak about Calgary itself because of terms of my employment, but I will say that dispatch centers can only patch channels if they have those channels at their centers. And for most dispatch centers, it's not as simple as dialing in a frequency in software and making the link - there is actual hardware that must be purchased, and someone has to pay for that hardware.
To my knowledge, CFD has no digital talkgroups - they're all analog. The guy who programs Redwood's radios once talked to me about testing some digital talkgroups, but I've never heard anything since.
Whether a system is analog or digital has nothing to do with its capabilities in this regard - just how it sounds, more or less.
I worked as a firefighter on the big grass fire that took out 320 acres along Highway 1 on April 1st. Crews from Redwood, Springbank, Cochrane, Balzac, and Calgary were there. We were using:
Redwood repeater 1 (Redwood Meadows crews)
Redwood repeater 2 (Redwood Meadows, Springbank crews)
Redwood tac 2 (UHF MUTUAL 2) (Redwood Meadows, Springbank crews)
Calgary Trunk C16 (Redwood Meadows, Springbank, Calgary, Balzac crews)
Calgary Trunk C6 (Redwood Meadows, Springbank, Calgary, Balzac crews)
Calgary Simplex B9 (Redwood Meadows, Springbank crews)
Cochrane Fire Repeater (Cochrane, Redwood Meadows, Springbank crews)
Cochrane Tac 5 (Cochrane, Redwood Meadows, Springbank crews)
The 700MHz system will get rid of all of that duplication and non-communicability (notice that there are some departments who were not on one system or another). All those opting in to the AFRRCS will be able to communicate with one another. We would only have had to use one dispatch channel and one fireground channel on that fire.
Having said that, this isn't the place for discussion about AFRRCS, despite the fact that some people want so badly to shoot it down. I'm not going to talk about it any further in this thread.
Provincial Firetac, 156.855, is used by many departments in the area as a fireground channel and/or interoperability channel - but only those who use VHF as their everyday comms. There are many departments in and around the area which use UHF as their main communications channels, and for them, Firetac isn't so useful. For those agencies, the province has the two "mutual" channels, 412.55 and 417.55.