is there a way to limit the number of users hitting the share?

i know i can use the share properties to limit the number of users...but how would i feed that into an error code for my script?

i assume i could do copy and if it dies use the error code...but with the current layout i notify the users via message box that a copy is about to occur before i actually start copying.....so they would get one "about to copy" message box and one "oops, it's to busy"....

tia,
justin