The short answer, is you can do it, but you have to treat them as two different locations, each hub controlling its own devices and not able to see the devices belonging to the other hub.
I don’t know if the fact that they’re on two different zwave frequencies would cause any additional problems, though.
If you go Somfy Glydea, there is a ZigBee Plug in Module and if my memory is correct both US and EU are 2.4ghz on zigbee, so no second hub would be needed.
Nope, that won’t work glydea is its own system, but I did some googling and there is a somfy Zrtsi interface for zigbee. You’ll probably have to write a devicetype for it, but it will still keep you on 1 hub