We have a situation at work where we are about to share a space with another company. To stop duplication of Wifi infrastructure, we plan to share Wifi Infrastructure.

My plan is to have our switch stack, loop into an access port from our switch stack to an access port on their switch stack, then go up a trunk, which includes their and our WiFi networks on some shared APs with separate SSID's.

The issue we are having is a clash of subnets, both wanting to use 10.10.x.x. 

My thoughts are this actually isn't an issue, as from our perspective, they are simply piping a VLAN from an access port, up a trunk to an AP. There is zero routing between our VLAN/their VLAN and therefore the traffic inside the VLAN doesn't really matter at all.

This makes sense in my head, but I've got a workmate who is adamant it's going to cause issues/not work.

Any input greatly appreciated.