An exchange of point guards between Houston, Toronto, and Phoenix might work.
Houston signs and trades Dragic to Phoenix
Phoenix signs and trades Nash to Toronto
Toronto trades Calderon to Houston
Probably some other considerations thrown in there to make numbers/returns work for everyone. But I think the potential for everyone to benefit is there. Phoenix and Toronto get their PGs for the next 3-4 years, and Houston gets a starting caliber PG on an expiring deal in return.