ecommerce - payment to different merchant accounts

I have an unusual ecommerce request from a potential client.

The client represents a number of service providers. The client would like visitors to their web site to be able to purchase a service from one of its service providers. Payments need to go directly to the service provider, not the client (non profit organization).

I intend to use Authorize.net for the credit card payment gateway. Ideally I would like to specify which of the service provider's merchant accounts should receive the payment.

Is it possible to set up a way for Authorize.net to make a payment into a given merchant account?

Thanks for any help.