Multiple foreignkeys possibility in Model Relation?

[archenroot]

This is issue already asked on core loopback tree:
strongloop/loopback#2080
on loopback-connector-mysql tree:
loopbackio/loopback-connector-mysql#150
and on loopback-connector-postgres
loopbackio/loopback-connector-postgresql#184

I am in the same situation on Oracle database.

So basically achieve following in model definition:
"foreignKey":["id1","id2"]