Resolved Unity MARS Replicator on one plane

Hello, is there any best practices to replicate multiples objects on the same plane while extending this plane ? I saw on the MARS Sample in the advanced scene, a replicator was used on a horizontal plane with 9 spawn objects. The problem is if the plane is too long its impossible to add spawn points on the other side.

 

Thanks a lot, that was exactly what I was looking for.