You should be able to use something like this to check:
If [ Evaluate ( Get ( LayoutTableName ) & "::Omit" ) = 1 ]
Set Field By Name [ Evaluate ( Quote ( Get ( LayoutTableName ) & "::Omit" ) ; "" ]
Alternately, I think you could provide a custom menu option for this but, IIRC, you will need to refresh the installed menu after each call to the command and on loading each request.
Do either of those approaches help?