@Phoenix_Rising - re: guidance around @mentioning - ditto what @Zoe7 suggested 🙂
The other strategy would be to do two separate posts, one which @mentions the people you want to, premising it with something like 'hi @sfjlf @asfjlfj etc etc - In a moment I'm going to post today's session about.... xyz.. this could be trigging or a bit heavier than usual, so I thought I would give you a heads up before I post it. If you're interested, jump into this discussion and check out my next post' and follow on with a post, not tagging those people.