I've got two motion sensor light fixtures on one switch. The manufacturer says each has to be on a seperate switch or they interact with each other and won't work properly. Well, they don't work properly, and I want to install three more fixtures outside the house. I can install more fixtures (and other stuff in the attic, if need be), but I can't install more switches. What type of isolation, filtering, accessories, equipment is needed to permit all of the fixtures to work off one switch?