Error in federation two subgraphs

Hello community, could you help me with the following case: I have 2 networks that I am trying to federate with a 1 to many relationship as follows:

this is Subgraph1:
type Resource implements DefaultConfig key(fields: “id”) {
id: ID
resourceSpec: resourceSpecification! provides(fields: “id name”)

type ResourceSpecification.
key(fields: “id”)
id: ID external
name: string! external

this is Subgraph2
type ResourceSpecification key(fields: “id”) {
id: id!
name: String!
quantity: Int
resourceType: ResourceType
reconciliationRule: ReconciliationRule
resourcePropertyTypes: [ResourcePropertyType] [resourceSpecificationRelationship: ResourceSpecificationRelationship
resourceSpecificationRelationship: [ResourceSpecificationRelationship] [ResourceSpecificationRelationship] [resourceSpecificationRelationship
resourceSpecificationItems: [ResourceSpecificationItems] [ResourceSpecificationItems
vendor: Vendor

I need to figure out how I could establish a communication between my graph 1 and graph2 in a bidirectional way, actually I have tried several solutions including the Compound keys but I don’t see a way to connect my resourcespecification to get all its associated resources list.