hi, i'd like to have the metal contact strip my transistor graphical pcell grow in the y direction according to an expression (width - 2*myVar) where myVar is a previously defined variable. the problem is that when i put the stretch line down it overlaps the diffusion under the metal also and when the cell grows in the y direction the diffusion is affected by this stretch line. how do i specifiy a stretch line on the pcell that will only affect one of the layers underneath? thx