I need help with Facebook group statics.

can anyone help me to know how many members added to my group by other members
I mean I need a data tool that analyzes my group and tells me the number of members added by anyone
I want to create a contest for my group and give my group members reward for each member they add to the group BUT I can't find the tool that tells me how many members added to the group by every member.
Can I get help on that, please?

Thanks.

This is the instagram section lmao