when a single seller doesnt input a paypal email address the global cart fails to progress to checko

Hi there
Is it possible to add a check somewhere to make sure a seller has put in a paypal email address in their settings, before they are allowed to have products on sale? When I buy items from 3 different sellers, if one of the sellers hasn't added a paypal email address in their shop settings, the cart doesnt allow a checkout because of the following paypal message, even though the other sellers have correct settings.

There was a problem connecting to PayPal to setup your purchase. Please try again.
13115 - Seller ID Missing. - Seller ID is mandatory for parallel payments.

This message would be meaningless to a purchaser.

It could just be something like - if the paypal email address doesnt exist , then the add to cart button is disabled