Blocking of Stock Posting after doing Usage Decision

Hi Gurus

How to make a setting for the following scenario?

1. When user is doing UD as Accepted

          a. Then he would be able to do stock posting only to Unrestricted Use and rest of the fields to be greyed out or system should restrict him to do stock posting in another field.

2. When user is doing UD as Rejected

          a. Then he would be able to do stock posting only to blocked stock and rest of the fields to be greyed out or system should restrict him to do stock posting in another field.

3. When user is doing UD as Partial Acceptance

          a. Then he would be able to do stock posting only to Unrestricted Use and blocked stock and rest of the fields to be greyed out or system should restrict him to do stock posting in another field.

I am waiting for your valuable suggestions

Thanks

Aditya