This covers at least the Mutants and Masterminds system. I would prefer an answer for 2E, but anything extensible to 3E would be handy too. If there's a generic d20 rule that applies, that would probably work as well, since the Mutants and Masterminds system is descended from that base system.
Basically, I recently had a situation where one character was using Hide in Plain Sight and rolled a good Stealth check. Another character had Magic Awareness as a sense, and rolled a high enough Notice check to spot the hidden character by the magic they were radiating. They spotted the hidden character, and tried to point them out to another character. It seems like being able to point out where a hidden person is would give some bonus to spotting them, but I'm not sure how much. Is there any rule that covers this?