In the attached image you find the circuit for which I'm supposed to figure out the values for the resistors R2, R3 and R6. I can have the switch S1 in ON and OFF positions. I'm supposed to take only the voltage between A and B. All other resistors have their resistance values showed in the circuit's figure. I don't have any information about current.

I couldn't progress much here, I tried several approaches, like coming up with the mesh equations and so on. But I couldn't isolate the unknown resistors. I always end up having more variables than equations.

I'm not asking for the equations, just some hint on how to proceed here, so I can try myself.

Any help is welcome. Thanks a lot!