hi experts, restricted value through F4 help

hi all

in alv grid output there is a input enabled field say xyz, this field is given f4 help by creating ztable, and when f4 is pressed on xyz field, it is fetching all the data related to that field, but the user wants restricted value with respect to company code and land1.

how to restrict the value coming in through F4 help ???

thanking u in advance

rocky