I grew up in the 60s and 70s in steel mill and coal mine country. I have many acquaintances from my grade school and high school days with whom I've stayed in contact. I already know how they would react to me coming out as trans because I've seen their reactions to others, both gay and trans, over the years. So I keep the accounts separate. It lets "him" send a polite congrats or happy birthday to stay in touch without adding unnecessary drama to my life. Given that I live over a thousand miles away from where I grew up, I never see any of them. A few live within a few hundred miles of where I live but the odds of encountering them are nil and none unless I went looking and I don't plan to do that.
And if it ever becomes public knowledge and people get ugly, I'll answer truthfully to those who ask. If someone decides to be ugly, they'll get unfriended and blocked, ASAP.
But in the meanwhile, for that particular group, I just let sleeping dogs lie.