Two logic circuits controlled from two SPST switches?
Yes, you can combine them &mdash; in fact, it's rather straightforward:







simulate this circuit &ndash; Schematic created using CircuitLab

Your question is not entirely clear about whether the 12V applies to the switches or the loads, so I've kept the diagram completely generic. The coils on the relays need to match whatever the switch power supply is in terms of voltage and AC vs DC. Note that SW1/RLY1 and SW2/RLY2 could also have entirely separate supplies if necessary.

You also didn't indicate whether C1 and C2 need to be isolated from each other, so just to be safe, I kept them separate.

RLY1 only needs to be SPST, but RLY2 needs to be DPDT. Of course, you could use DPDT in both positions and just ignore the extra contacts. And if C1 and C2 don't need to be isolated from each other, then RLY2 can be SPDT.