Trouble growing group

My group was recently destroyed by someone who kicked everyone out. We now have 21 members and dont know wuat to do. We ran multiple advertising campaigns and they have never worked. Here is a link Sandy hotels and resorts - Roblox can anyone help me to think of a way?

Advertising to friends and letting them ad to their friends etc etc.

That never really works. I try it often but the group members are quite inactive