That is great if you have a ton of spare money to outfit all your field people with these high priced toys. Your better off buying 2 lower cost radios for what those go for. Plus then you can monitor both bands at the same time. The dual band radios only have one receiver in them so what ever band shows up first, that is what you listen to. The conversations on the other active band get lost.
If your only using one band at a time, then this is not an issue. But having been out in the field working with public safety systems for over the last 45 years, I don't see mutual aid and multi agency incidents using only one band. They have to rely on some sort of a patch if you want everyone to be in on the activities.
As for equipment to patch multiple radio systems together, there are a number of units out there. The selection comes down to just what features you need. The state of Virginia faced just this same issue about some 5 or more years ago. They went out for bids and the Sytech Corp from Alexandria, VA won the bid against all the big time players. Since then they have come out with field tactical units that have been a big choice of many of the federal agencies and many of the public safety agencies. Do a search for the "Virginia COMLINC Project" and read all about what the state did. They have some 130 plus dispatch centers and mobile command vehicles on line 24/7 with gateways.
Another waste of taxpayer money to fund high priced systems that only line the pockets of radio companies,I am so sick of this digital push and the outrageous cost of what some consider worse than the system they have in place now,the FCC wants to sell off all the frequencies we use now to the highest bidder...what kind of smoke and mirror tricks will be next to line everyone's pockets at our expense?