Validation rule

Hi All,

There is a requirement of writing validation rule in FI.

Requirement: GL line item text field BSEG-SGTXT must be made mandatory in case if it is blank for the selected FI transactions . for e.g. FB01 but this validation rule should not apply for cross company code documents.

What validation rule needs to be written in GGB0?

Kindly help.

Regards

Anuj