They stole the "ground" from the exclusive British Plymouth Brethren, who also have a checkered history of lawsuits, divisions, and excommunications.
Nee was a part of the Exclusive Brethren until he committed a "mortal sin." He joined a communion service and "broke bread" with a part of the "degraded, divided, condemned system of Christianity."
Here is an interesting
article about W. Nee and the Exclusives.