Ganesh,
- Usually, what happens is (in every module) functional way of having checks such as present requirement, might have limitations sometimes. Then user-exits come to rescue. But one should be able to identify proper Exit/BAdi and code it suitably. Why I'm writing this is, in case you have issues in Customizing route of achieving your requirement, still user-exit could give you a way-out.
- So first try Customizing route using inputs received which includes asking experts in MM space if necessary, then explore Workbench route (user-exit).
Good luck
KJogeswaraRao