according the manual "VE.bus firmware version explained", it should be no problem, to match
https://www.victronenergy.nl/upload/documents/manual-VE.Bus-firmware-versions-explained-EN.pdf
2x MultiPlus-II: (software 2629481)
1x MultiGrid-II: (software 2625481)
together to a three phase system.
I use the latest VE-configuration tools, but it is not possible to do this.
An error messages in VE-Bus Quick configure tells:
Only Multis of same kind and with same firmware version are allowed!
Procedure will be restarted
Switch all devices off and press OK
What is the probleme?
Best regards
Roland