Validating Plant & Business Area

Hi All,

We have given the following plant with business area, but the user could change the plant with other business area.

Plan : 1100 1200 1300

Business Area : 1100 1200 1300

So we need to write a validation, could you please help me how to do validate both, so that if the user enter 1100 plant with 1200 BA he should get a warning message.

Thanks in Advance.

Regards'

Syed

SAP PS Consultant