zero the perimeter of a blob

Hello everyone, I'm trying to solve the problem of overlapping gaussians.I want to zero the overlapping areas.I have abuted to an algorithm but it doesn't zero the perimeter of the area.I've tryed bwperim but it didn't work.I found the coordinates of the perimeter but finally it zeroed the inside of the spot but not the perimeter.

[Andrew Newell]

You use the word "perimeter". Are these Gaussians in more than one dimension? Some code showing what you have done would help.