How easy is it to manage payments going only to admin account and then dispersing to vendors?

I am just curious how the payment process works with multiple vendors. I know we set up the main account for example if we use Paypal we would have it set up so that the payments go to the main account setup for the site but I just wondered how it works with getting the appropriate monies to all the vendors when they make sales as they cannot set it up to for the payments to go to their specific Paypal account. I know we have to setup the commission we will get from those vendors and we have done that but do we have to manually figure what needs to go to each vendor or does the site do that and then we just manually send the amount to the vendors through Paypal? Any info anyone may have on this process from their experience will be EXTREMELY helpful! Thanks!