Limiting values to a variable
I've the following scenario and would need your help to find a solution.
1. A Z tables contains a mapping for the user names & institution ID's.
2. The user when executing the query should see only the values that he is mapped to in the Z table.
3. I created a Customer Exit Variable and populated the values allowed for the user.
4. On the selection screen the user is seeing the values he is allowed to see. ( he might see 2 values for example).
5. However, the user can enter any other value.
Question: How can I limit the user to the values in the selection such that the user cannot enter any other value ?
Also, handling the above scenario with the authorization objects is out of question for my case.
Any help is appreciated.