Resolving fields from other service

Hey there, I’m using apollo federation with additional schema stitcher layer where I implement subscriptions. In that subscription as payload I get an object, in my case conversation, this conversation has ConversationParticipants, however they are not getting resolved. Conversation and ConversationParticipants at this moment stands in the same service. However, as I see the problem is that I’m trying to resolve ConversationParticipants from my schema stitcher layer where my subscriptions stands. Am I correct? If I am, how would you go about solving that? Would you use resolveReference? Does it work if not a singular entity, but a list of participants? Would appreciate your help tho