Gst on dropshipping

Hi I'm developing a marketplace website allowing Suppliers to sell their product. In addition to that I'm providing Dropshipping option as well. Anyone who registered as Reseller can use the product images from Suppliers and Sell to their customers. Customer will know Reseller only and when order comes , product will be shipped directly to customer. Here Reseller don't do any inventory and don't see the product in physical but he set his own profit. Let me explain with example . Supplier A lists his products in site for Rs.1000. Reseller B has taken the image and sharing with his customers or Resellers again for Rs.1200. Reseller C can share the image again to his customers or Resellers again at Rs.1400/- So when customer purchases from Reseller C for Rs.1400 I as App owner will split the amount as Rs.200 to Reseller C, Rs.200 to Reseller B and Rs.1000 to Supplier. I'll take commision from supplier and resellers. For commision invoice I can create. I wanted to know how to create invoices as per GST for Suppleirs and Reselelrs for Goods supply?