Thanks to all. i solved the problem, its not hanging now. Thanks a lot.
Arrch: You can do it with a relay, transistor, diode and a resistor. You could even get a solid state relay and drop the transistor and resistor.
Ooops, Transistor will create problem in the circuit you said. and i tried it too. Optocoupler isolates two circuits which i exactly want.
Thanks for your suggestion.