Stopping a movie on a selected frame

i can’t figure out how to do this…
ok, here’s what i need. i have a movieclip that plays, (its bars on a motion guide) and i want it, depending on a variable to play to a certain frame. so, lets say the variable = 1 then i would want it to play until it got to frame 15 then stop, if the variable = 2 then i would want it to play until it got to 30. i hope you understand what im saying…
thanks