I have recently had successful cross-reservation interlining for KL (SFO-AMS) to SU (AMS-SVO). The check-in staff at SFO was from AirFrance as far as I could see.

They clearly understood my request, but it took about 10 minutes to get this done (with about 3 people involved), because apparently they don't have to deal with this too often, and agent I originally approached hadn't ever done it before.

Btw, nothing showed up in their system automatically, so they manually entered information about my SU flight.