This solution covers inventory sharing relationships, where different entities (app/site owner, content owner) may have the right to sell ad space within a piece of content on a given app/site.
Gamoshi support Inventory partner domain - in the form of a new mapping rule for demand partners.
The field value is usually a domain, and its mapped against bundles.
When a site or an app contains ad inventory that is owned by another partner - the app or site should list all domains for those partners by using the mapping rule TO property: “Inventory Partner Domain”.
You can use the mapping rule for a scenario where publisher A have ownership of (and rights to sell) some inventory on app or site B.
For more detailed information refer to the IAB documentation at: IAB - Inventory Partner Domain