Validation rule

Hi

Please help me in writing validation rule for restricting the usage of T-code FBRA with a combination of two Bank GLs to a limited users.

That means all users which are having authorisation of FBRA can reset and reverse any document which doesn't have the above GLs in line items. All users cannot use FBRA if any document contains those GLs mentioned in above validation rule. But those previlaged users which user names are mentioned in the GS02 can use FBRA to reset and reverse any document, whether it contains above GL or any GL.

Please suggest validation rule.

Regards

Prakash.