See Fair Work Act 2009 s.172(3)
Two or more employers that are not single interest employers may make an enterprise agreement with the employees who are employed at the time the agreement is made and who will be covered by the agreement.
A special stream of bargaining for multi-enterprise agreements is available to enable low-paid employees who have not historically participated in enterprise-level collective bargaining to make a multi-enterprise agreement. The Fair Work Commission can make low paid authorisations that allow access to this stream.