I have two problems with this. First of all, supporting existing hierarchies is neither radical nor feminist -- privileged "activist" groups should not be excluding those with less privilege. If you didn't learn from first wave feminism's "only upper/middle class straight white women count" mistake, go back to feminism 101 and leave the organizing conferences to people who care about more than one-step-away-from-privilege-pinnacle people. UGH. Your privilege reeks and you're splashing it everywhere.*
Second, the idea that having an exclusive gather based on external bodily characteristics automatically gives some kind of safety/freedom from privileged/oppressive behaviors. NO IT DOESN'T. It's a simple way to find MOSTLY safe people, but it's certainly not the best way. Exclusive gathering is a false sense of security -- it excludes people who might look different but would learn and be respectful, and includes people who might be trying to impose their internalized oppression on others who are the same. I would never try to push my way into a gathering that didn't want me, but I also would never form a gathering based on some external similarity to me. If I was having a meeting about being classed as female, or being queer, or being trans, I'd set the topic and set rules for behavior, and let people agree in order to join. If I wanted to create a sense of safety, I might have a behavior rule that said, "if you have not experienced this, attend to listen only." More likely, I would use some variant of numbers 3, 4, 5, & 6 of my house agreements, perhaps with volunteer bouncers just in case someone could not be civil.
The idea that because someone has experienced similar oppression they will not visit that oppression on you is sheer ludicrous error. I've experienced silencing, policing, 'splaining, shaming, erasing, and other tools of the kyriarchy being used against me by female, queer, trans, poly, fat, etc people. And I know it's not just me. I'd trust someone with more privilege who was willing to be called on it and stop over someone who merely had similar oppression ANY time.
*on the bright side, at least I didn't go to the conference unaware and get surrounded by that shit.