Joining several network using a router then taking them apart again on the other side?

Hello forum I am new here, I have used mikrotik routers before but not for a project like this. We have a project to do the network is very large and we cannot tag vlans through the network as they want them to remain physically separated. The wireless link is already in place now we need to take three physically separated networks join them to cross the wireless and separate them on the other side without mixing or bridging the networks. The buildings are miles apart to be able to connect with other means or too expensive.

I am looking to purchase Mikrotik routers (8) possible CCR, but before I purchase I need to see if there is a viable solution to our dilemma. Will the ccr routers be able to do this and if so do you guys have a sample config on how this might work. Any help will be greatly appreciated.

Juan C