Searh help for f-28

Hi,

I have put a search help on "Doc. Header Text" and "Assignment" fields of tcode f-28. I have attached it in the layout of the screen. But the problem is that the same screen is being used for tcode f-53 and thats why these search helps are visible there as well. I wish to ristrict search help only to F-28. Can anybody please help me with this requirement.

Thanks in advance.

Regards,

Dhiraj