The only way to pass the site's Integration ID is at the site level, currently. We have some customers who have multiple companies within PressWise, but only 1 site in Pressero. When we receive an order from one of those companies, we have to manually update the order in PressWise after it is received to set the correct company.
We don't want to have to build multiple sites, since for the most part, the products are identical, just the customer they get billed to is different. This could also be used to create individual products on our own primary store for users to order from without having to create a separate B2B site for each one.
I would like to be able to override the default site Integration ID at the user level to specify a different customer within PressWise.