OK, so here is a conclusion.
It didn’t work, unfortunately. In closed crew session some crew members were unable to join, for unknown reasons. When we switched to friends only session, things got complicated too. It appears that this session was open only for host’s friends. I hosted it and I had no all crew members on my friends list (like Vix). Simply saying, friends of my friends were unable to join too.
At least we tested it, but looks like invite-only session is still the best solution…