Yes, you can call Member Services for your dining reservations.
Reservations have nothing to do with where you're staying, no matter whether you book through MS or WDW-DINE. They may ask where you're staying, but that's just for record-keeping, and to see if you're eligible for the 180+10 reservation window. They won't ask where the other members of your party are staying. Anyone can make an ADR - onsite guests, offsite guests, locals, etc.