Lending app

I need an ios and android app. I would like it designed and built. The app is about monthly payments. Payments from users of group And one of the group get the whole amount The next month 2nd user get the whole amount each user will pay each month? and get whole money at a month later? Admin from backened will set group number and the duration Admin will set minimum and max amount that user can pay And then let say there are 100 user in app and admin specified number of members in group to be 12 and minimum 100 and max 500 1 users from 100 users paid 350 System will automaticly create group of 350 And user will be in that group Now this group will be shown for people but if they want to join they need to pay 350 Now this group will be shown for people but if they want to join they need to pay 350 Until group is full Now lets say another one paid 315 It will create group of 315 Group of an amount of 315 with max user in 12 And another user wants to pay 315 monthly in app so he will join that group If that group is full he will start new group User will pay and get paid via paypal and myfatoorah Also user can create group and invite users to join But payments wont start Until group is full and everyone paid And to know who will be paid first 2nd 3rd ... etc I was thinking to do spin and will show user name in that group Then users get number from 1 to the max number admin set User will need to submit some documents to admin via app and they will receive verfication code to verify their mobile number Admin will % commission monthly , yearly admin will set it up