I think anytime you get involved with small religious groups that have non-mainstream beliefs dominated by a single person you are likely to have some issues.

The problem with suggesting joining for instance the Mormon church is that while their views of secular things such as preparing for possible disasters of various types might well match up with your own, their religious views might be far outside of your own.

One thing nice about the Mormons is that they are pretty free with disseminating their collective wisdom on prepping without trying to force their religious beliefs on one. They even make their bulk food products available with minimal hassle to outsiders, although as I understand it, this is done on an unofficial "as available" basis, which is not real surprising as it is primarily done to benefit their membership.

It is too bad there are not Boy Scout type groups for adults, although to some extent volunteer fire departments and SAR squads are kind of an extension of the BSA philosophy.