I was thinking that he said he couldn¡¯t even send a msg to the yahoo group. Therefore, most members on the group might be hesitant about moving with a ¡°stranger¡± to a place they aren¡¯t familiar with. If he named the new group on yahoo similar to the old one on yahoo, they might be more willing to try it out.... maybe? Then once everything got explained, they¡¯d be willing to move to a whole new home with groups.io
Just a thought ¡®cause I know how I¡¯d feel in a similar situation.