Interfaces and providing type field data in another subgraph

Help
,
1

I am migrating a large, complex schema to federation, and have encountered a scenario with Interfaces and resolving field data across subgraphs I’m not sure how to solve.

Games subgraph

interface Game {
  id: ID!
  sport: String!
}

type BasketballGame implements Game @key(fields: "id") {
  id: ID!
  sport: String!
}

Feed subgraph

interface Consumable {
  id: ID!
  type: String!
}

extend type BasketballGame implements Consumable @key(fields: "id") {
  id: ID! @external
  type: String!
}

extend type Query {
  feed(user_id: ID!): [Consumable!]! 
}

I’d like to be able to use a @provides directive approach to tell the Feed subgraph it can resolve the sport field, however I don’t have a concrete type to annotate. I know I could handle this so that the feed query gets the game data from the game subgraph, but it would be trivial for the feed query to return at least the base level Game fields itself so performance wise that is less optimal. I could add a FeedGame interface in the Feed subgraph and add that as an interface the BasketballGame type implements but that would break existing queries.

I’m still coming to grips with Federated schemas so perhaps I’m missing something, thanks.