I'm pretty new to VKB, waiting on my 2x Kosmosimas with GF MK.III

I have a question, probably really stupid. But as i have read is that i will get 1x black box per MK.III unit. Can I plug both MK.III in to just one black box (noticed the black box have 2 connectors) or do I use both of the black boxes to control one MK.III each ?
Tried to find the info but couldn't find a straight answer.
