5 parallel internet connections, each connected with a wireless network card and assigned to a machine, right? That doesn't seem like a problem for any type of motherboard, and a current standard system (socket 1150) supports up to 32GB and up (socket 2011) 64GB. Depending on whether you make those virtual machines, one hard drive or another will be better.

If it doesn't work correctly, it may be a problem with the cards or signal reception, so many signals together in such a small space must be well divided among several frequencies, although the ideal would be a wired connection. What problem do you have to find a motherboard?

To give an example: Asus P9X79 WS 90-MSVDR0-G0UAY00Z Motherboard