Enhancement in MRS to restrict Demand assignment

Dear MRS Experts,

    I'm looking some exit in MRS for demand assignment to resources. My requirement is to trigger the demand assignment in MRS planning board, based on demand status. First I'm checking the material availability against all the demands and based on that if material is available setting a status AVLB or if missing setting MISS.

Now while doing the assignment of demand (either manually or automatically) need to check if demand status is MISS, system should not allow to do an assignment and prompt an error message.

Only if demand status is AVLB , demand should be assigned to resource.

My quary is - Is there any exit or enhancement available to make such check of demand status, during assignment trigger through which I can restrict to trigger a demand in case of condition does not match ?

Please revert with your views ..

Thanks in advance ..