Is it possible to connect 2 separate networks at the Access Point?

Hi,

I am working with a POS vendor that insists on having a completely separate network. Not subnetted or VLAN, but separate firewall, everything, but need the use of the access points. Is there a recommended way to do this? We would normally use VLANning, and in theory, I believe we could still use VLANs to accomplish this, but have never actually done a setup like this. Any recommendations?