Wordpress/Woocommerce Paypal Checkout takes to another website performs real checkout to paypal

I have a wordpress webshop and need a plugin or script so when someone performs checkout payment instead of going to paypal it redirects him to another site and selects a product of equal value and then performs the real checkout to Paypal from my second site. Sort of like a lottery chance purchase. I need help in setting this up. I will only have 4 products on site and they will not change.