I need a script that generates a PayPal Pay Now button so my users can pay each other

General information for the website: We act as a Sports Team Management solution, allowing members of the team to pay their monthly fees to their club manager online.
Num. of web pages/modules: 1
Description of requirements/features: I am a rookie website developer, and am in the process of finishing my website. Essentially, the website acts as a management system which allows the manager of a sports team to receive payments from club members, be it for tournament fees, kit fees, or other expenses.

I have set-up a system using PHP and CodeIgnitor that does everything, apart from the payment module. This is what is required of the freelancer.

I do not want to act as a payment gateway between these individuals. In other words, no money should be transferred through the business. Rather, I would like the users to pay each other via their personal Paypal accounts.

So, to explain the job in simple terms. I have two users, each with their personal paypal address stored within the system. I need a script/function/class that generates a Paypal 'Pay Now' button for the user, allowing them to pay the amount which is stored on their account, directly to the other users personal paypal address.
Payment methods: Paypal
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