Reddit mentions of The Ladies of the Wednesday Investment Club

Very sketchy. For one I couldn't find a website for the organization, just a bunch of little groups on meetup.com, although I did find a connection to an organization/company/not sure, really, that seems to be the backer: Private Financial Club.

Hell, someone even wrote a book parodying it.

All in all, the group looks like it's more of a club than anything, getting speakers to come and talk to them (like Anthony Robbins) and to exchange investing tips/advice/etc that they have come across since then. Almost like an investing support group.

Good for your wife for not joining. As for preserving the friendship, don't be hostile to her friend about this investment thing. Be polite, etc etc and quickly try to move onto another topic. Don't say anything to the effect of "I told you so" if her friend loses her money.