I too had it with just kids at school, this isn't the full SEX talk , I don't think. Just to prepare them about getting there periods. I never really had any talks with my mom, I was at my aunts when I got my first period, and I had an older sister in the house so there were already pads in the house so I never had to ask her to buy them. I don't know
if the boys are doing anything.
I too was thinking about doing it with the scout troop but I have such a wide age range right now. you might be able to get a nurse come talk to them, this is the RN at the clinic that comes in and is the school nurse,