Custom PayPal payments Module

ToolMates Hire is an online peer-to-peer tool rental marketplace, we are seeking a PayPal developer to create a custom payment module for our platform which is built on X-Cart. How to calculate payment: > We have created our own extension to the "Add Product" so when a user is adding a tool they can select "Bond" or "Item Guarantee" when they select "Bond" we want the payment module to work > But if they select "Item Guarantee" then this will pre-authorise the same as the "Bond" but also charges the Vendor who owns the tool an extra 12.65% of Item Guarantee Amount ( The Guarantee Amount is calculated automatically and stored in the database based on the 20% of the value of the tool). We will send on documentation with user experience and database design of our Tool Listing Module. > So the "Item Guarantee" is like a Insurance they can take out on their tool. But they must Pay us "ToolMates Hire" a extra commission 12.53% of Item Guarantee Amount. >The "item guarantee" amount will be deduced from the vendor payment and moved to the vendor commission. That part of the payment will be separated from the "Bond" amount and captured immediately. The payment will be split by following recipients: 1) Store owner 2) Product 1 vendor 3) Product 2 vendor ... 4) Product N vendor (up to 9 recipients will be available) The store owner will get a sum of bond payments from products in the cart. That amount will be authorized only. Other payments will be authorized and captured immediately. NOTE: payment fee will be paid by each vendor personally. Here is a chart showing how the payment will be split by users. Each order paid by Parallel Payments will show a form for capturing funds in the store back-end. A new 'Capture Funds' tab will be added to the invoice in the administrator section. The administrator will see the following information: - authorized amount total - expiration date The administrator will be able to define an amount of money for capturing and some notes for that operation. After clicking a "Capture" button, the customer will receive an email notification that the "Bond" payment of NN amount was taken. Additionally the administrator will be able to click a "Release" button for reducing authorized amount for the purchase when the tool is returned to the vendor. NOTE: authorized money can be held within 29 days only. Email on capturing Subject: funds were captured for Order #NNNN Body: <header> The administrator captured NN of authorized funds. <comments> <footer> Email on release Subject: funds were released from Order #NNNN Body: <header> The administrator released NN of authorized funds. <comments> <footer> Invoice on customer side Customers will see the same 'Capture Funds' tab but they will not be able edit anything there. They will not see a history of operations. When the admin captures/releases some amount, a record to the order history will be added. There will be two types of records: - administrator captured NN amount on 10/20/2017 - administrator released NN amount on 10/20/2017 Re-authorizations Within a 29-day authorization period, you can issue multiple re-authorizations after the initial three-day honor period expires. A re-authorization restarts the honor period. If you do a re-authorization on the 27th day of the authorization, you get only two days of honor period. We will create a cron script which will execute re-authorization of authorized payments so the funds will be kept untouched by the buyer.