Symotronic

Hi, I wonder if (on Paypal) it's possible to make reccuring payment regarding an external parameter in order to adapt the value of the payment for each user ? Example (normal reccuring payment is 15 euros) : - User A has a eWallet of 5 euros, the recurring payment takes 10 euros (15 - 5) - User B has a eWallet of 9 euros, the recurring payment takes 6 euros (15 - 9) Is it possible and if yes how ? Thank you! Nicolas