Jerry,
I do this all the time in NewSearch. Here is what I do.
When I find a person and want to know who else may be at that phone number or address I highlight and copy just the address or phone number, go to NewSearch, Paste the info into the keyword field and mark it exact and leave everything else- and I mean everything (including name)- blank, then hit search.
I've found names of husbands, wives, and grown children living with their parents this way.
ps- just saw your first post re; using keywords. Have you tried using Veromi or 123Peoplefinder? I've found them useful for finding other family members and sometimes they mention a woman's maiden name.