In reply to DK1AX:
There should not be any problems with those transceivers if you are not too close together as they are all QRP. I have been part of a group of 6 on a summit running a combination of HF and VHF and we experienced very little interference and that was running up to 40 watts output. I would suggest that if you are using dipoles then you do not align them all in the same direction and that you space yourselves out on the summits if you are able to.
As long as you are not operating on the same band at the same time, I am sure that you will be okay. I regularly run an 817 on 10MHz when another 817 is in use on 7MHz on the summit or 7MHz when 5MHz is in use without any problems.
73, Gerald G4OIG