unable to use 3 cameras

[RICHMURRAY]

im trying to use 3 webcam cameras for recording video on for my music. everything plugs into the interface and obs reads that no problem. The problem Im having is in regards to using 3 cameras. when i click on add video capture device #3 it doesnt even pick up the cameras(any of them including my laptop camera) .
does anyone have any work arounds or advice on how to over come this issue??