Glad it worked for you.
As others have noted, STRETCH command has a REMOVE option you can use to deselect objjects you don't want to include in a stretch function, before stretching. For some inexplicable reason this is not discussed in HELP in AutoCAD/LT but if you simply watch the commandline you see it after you've drawn your rectangle selection window for the command.
click the two points to drawn your all encompassing rectangle
now remove the objects you don't want to include in the stretch: use any selection method you want, even windowing.
now continue with your strech function.