Adding someone to signup who isn't a household member

I’ve created a signup sheet and sent it out. I have a few technically challenged folks in our troop that don’t understand what they need to do and instead have emailed me to see they want such and such a timeslot. I want to add them to that timeslot on the signup sheet, but the dropdown only contains members of my household. I’m our administrator and have full privileges, am I not able to add people outside of my household?

I have run into this issue myself and am not the only one. This has been addressed elsewhere on this forum.

Temporarily add those persons to your own household, make the changes to the sign up sheet as necessary and then remove them again from your own household.