How to connect 2 seperate subnets 3 rooms with limited cabling. Router configuration

I need the help of you network gurus.  I have 3 rooms (see attached picture).  In the first room, I need 2 pcs that are each connecting to a different subnet (they do not need to talk to each other at all).  The switch for the first subnet is in room2, the switch for the second subnet is in room 3.  Here is my problem, I CANNOT RUN A NEW CABLE.  So I have to figure out how to do this with a single jack in each room.  I can put a router or switch or whatever you tell me in any of the locations, its the cabling that I am limited with.

Please be fairly specific with the setup (please dont respond with just put a router in room 2).  I feel that a patch cable in room 3 from switch to wall jack d is pretty obvious.  But then I feel that I need something like a router in room 2 that is plugged into the switch and Wall Jack C to allow traffic to connect both networks.  Then maybe a switch at wall jack a?  But how do I configure the router to accept traffic coming from wall jack b to understand what traffic goes to the 192.168 network and what traffic to send to the 10.10 network?
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