Stealth, if they're not allowed to divulge information, that doesn't prevent them from listening.

So I think a person who was interested in research would explain to the R&D guys and/or girls what their previous studies and work had involved, what skills, knowledge and expertise they had acquired and explain to the R&D people what area of research they were interested in getting involved in.

If they were potentially a match for whatever secretive research was going on, and if there were vacancies, then I'm fairly sure they would find out. If their profile didn't match the research area or there weren't any vacancies, then things would come to a dead end.