Does anyone have advice or success story about safely starting up a masturbation group for mature guys? How to find folks and get started? Would like to stroke with other men - safe sex only.

it would be fun ...

It seems a lot of guys are interested in this but have the same problem about finding like minded people. I guess posting here is a start and do the same on the jackinchat discord site, there is a section for jacking requests there. Im not sure if anyone has had any sucess there but there are a lot of posts.
Good luck!

The local one I attended once was one I found through a simple web search and finding their Yahoo group. They'd been around for a while.

You might also find some tips from the Heart of Jacks podcast, hosted by the organizer of Seattle's Rain City Jacks.

IRL you'll struggle, but I hope you make it happen!

There's always a distance barrier, and trust issues invariably occur.

Other than that there's obviously Skype and whatnot.

Always looking for fun groups to join with like minded folk. Kik was good but seems to follow the newest app or social media and every jumps ship. They are brilliant though