EDACS systems MUST be in channel numbers that correspond to the LCN number.
If you have two systems that use DIFFERENT LCNs with no overlap, you can put them in the same bank, but if they do overlap, they will interfere.
Scanning may be funky since scanner will stop on the first control channel, and if there is traffic go to the LCN indicated in the datastream. But if there's no traffic, it will continue to scan, and then find the other control channel. You may (I'm not sure) need a conventional freq between the two control channels.
You'll also have confusion over talk groups, unless there is no overlap in them, either.