It takes a leap of faith & huge amount of trust to get the vetting side of connecting with others right - or as safe as it's possible to be.
FWIW from my experience, you need to be certain the person who you are allowing into your group is real, who they say they are, and are happy to disclose their online ID/accounts for checking. I'd also recommend meeting in person in a public place to be able to have a conversation in person as it's far easier to maintain a false front online than it is in person.
These are all steps I've taken when agreeing to include someone in private spaces/groups with other women & even with those steps you can never guarantee the person/people you are dealing with won't turn out to be a problem.
Never give away personal info that can be used to cause you trouble. Don't mention your place of work, your home town, your kids, any schools or other identifying information to anyone unless you can be sure they're trustworthy. Even then I'd urge caution. And I'd ask others to think about the sort of Qs you are asking in a group like this that you want to be part of - asking others for identifying personal info is unnecessary & actually places suspicion on you. In most other settings, it's probably a natural way to try & get to know people - but in the context of these groups, it's really not appropriate.
Just my tuppance-worth. Feel free to ignore.