Actually i know that we cant...
But i need alternate ways to fulfill that requirement..
suggest me if anybody have any alternate ways to solve that....
Discussion posts and replies are publicly visible
A common approach, which would be good for many use cases (but probably not optimal for all) -- have a dropdown as your "main menu"; then depending on the selection from that dropdown, show and/or enable a secondary dropdown either next to it or right below it, with its own options.
Thanks Mike.