Creating A Null Schema?

We have a vendor-supplied 11g database where records are split between two schemas -- an ACTIVE schema and an ARCHIVE schema. Each object has both a corresponding object in both of the ACTIVE and ARCHIVE schemas.

The vendor also has a third schema where each object is merely a UNION ALL of the associated ACTIVE and ARCHIVE schema objects. For the sake of example, I'll call that schema COMBO.Over the years, we've created queries and reports that reference both the COMBO and ARCHIVE schemas and that has worked just fine.

The vendor has now set up a secondary database for us that we can use when the primary database is offline for patching/upgrades/etc. The trouble is, this secondary database only has the ACTIVE schema and records. The vendor will not be writing any ARCHIVE records to it.

Primary DB: ACTIVE, ARCHIVE, and COMBO schemas
Secondary DB: only the ACTIVE schema.

is there a way to set up the missing ARCHIVE and COMBO schemas on the secondary DB such that we won't have to rewrite our SQL to accomodate the lack of an ARCHIVE schema when we move reports over to the backup database?

Of course, no records would need to be returned from the virtual ARCHIVE schema, but I'd love for the untouched SQL to run without error.