Correct way to pass additional arguments from a field resolver to another subgraph?

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Hello! Is my first approach to graphql federation, I’m trying to understand what can I do (and how) with the directives.
So, let’s consider a simple supergraph example composed by 2 graphs: auth and profiles.
auth store login information, and profiles things like billing and shipping address, company and user profiles.

In the auth schema I have:

type LegalIdentiy @key(fields: "identity_id", resolvable: false) {
  identity_id: ID!
}

type OrganicGroup @key(fields: "og_id") {
  og_id: Int!
  name: String
  legalIdentiy: LegalIdentiy
}

and auth resolver for OrganicGroup entity:

  OrganicGroup: {
    legalIdentiy: async (reference, _context) => {
      /* some logic */
      return {
        identity_id: reference.og_id.toString(),
      };
    },
  },

and then the profiles graph:

type LegalIdentiy @key(fields: "identity_id") {
  identity_id: ID!
  identity_type: String
  legal_name: String
  street_name: String
}

with his resolver:

LegalIdentiy: {
  __resolveReference: (reference, a) => {
    /* some logic that populate result*/
    return {
      identity_id: result.id,
      identity_type: result.type,
      legal_name: result.legal_name,
      street_name: result.street_name
    };
  },
},

now the question is, how do I pass arguments from the auth’s OrganicGroup field resolver to the profiles LegalIdentity one?
Those arguments should not be part of the query, and may trigger some logic in profile’s __resolveReference function.

So far i’ve been able to do this only using @inaccessible directive, so in my auth example become:

type LegalIdentiy @key(fields: "identity_id extra_args", resolvable: false) {
  identity_id: ID!
  extra_args: String @inaccessible @shareable
}

and the auth resolver:

OrganicGroup: {
  legalIdentiy: async (reference, _context) => {
    return {
      identity_id: reference.og_id.toString(),
      extra_args: "custom value from auth subgraph!",
    };
  },
},

then the profiles graph become:

type LegalIdentiy @key(fields: "identity_id extra_args") {
  identity_id: ID!
  extra_args: String @inaccessible @shareable
  identity_type: String
  legal_name: String
}

…and in his resolver I can finally get extra_args value:

LegalIdentiy: {
  __resolveReference: (reference, a) => {
    /* reference.extra_args has the value from auth subgraph! */
    return {
      identity_id: result.id,
      identity_type: result.type,
      legal_name: result.legal_name,
      street_name: result.street_name
    };
  },
},

but even if it works so far, looks like a bit tricky/hacky to me.

So, there is a better way to achieve this result?