Restrict from posting of a particular plant in FI line item

Hi,

I have a scenario, a plant (eg. TN01) operation is stopped from MM side and the client want to stop posting from FI side as well. While processing F-02, after giving GL account, we have option to enter plant data in more tab, I want to restrict posting only for TN01 plant in line item.

I tried giving validation in OB28 like below but not working.

Prerequisite:

BKPF-BUKRS = 'TN' AND BKPF-TCODE = 'F-02'

Check

BSEG-WERKS <> 'TN01'

Error

Z8 Plant TN01 not allowed.

Could you please help me how to restrict from posting of plant TN01 in line item from FI side?

Thanks

Suri