One way of doing it that I know, is to have an invisible sprite that detects collision with the ceiling sprites. Once collision is detected, then it triggers "a Stick to ceiling " control group that overrides the usual movement.
Yung, your capx is exactly what i need, i understand the logic now. So much thanks again, very professional !!! Zsangerous and Ashley, thanks to you too guys. Its very helpful to have guys around here for help.