Ext Hard drives

Are there any restrictions or issues with external hard drives? I have recently tried an Android Box which struggled to read 2 of my external hard drives. I use 3 harddrives altogether. 2 of the hard drives are 7200rpm 4TB capacity and the other is 5600rpm 5TB. All hard drives are formatted in ExFAT.
Will the Vero 4K read all of the harddrives ok? Will it read all 3 at the same time? (All three at the same time isn’t a massive one but would be good)

In my experience You should’t have any issues as long as you use a usb hub with its own external power supply.

for example: 4 Port USB 3.0 Powered Hub - OSMC