I'm working on a Drupal 7 website where certain content elements are specific to individual partner companies (think, co-branding).

Everything works as expected, but there's a new requirement for the homepage, where a partner-specific version of the homepage (partner.website.com) should show only certain hero banners in the "slideshow," if they're "tagged" with that specific partner.

The tricky part is that there needs to be two different kinds of banners (content types); those that are tagged to a specific partner(s) and those that are universal for all partners, and both types should show in a single slideshow set.

As an example...

We have universal banners A,B,C,D (which will be displayed regardless of the partner).

partner 1 has banners 1A and 1B, that are unique to it.

partner 2 has banners 2A, 2B, 2C unique to it.

So then, if you go to partner1.website.com, you should see banners A,1A,B,1B,C,D. Going to partner2.website.com will show A,2A,B,2B,C,2C,D.

I'm using Views Slideshow to format the output of banners.

I'm leveraging a third related content type for the partner, by way of an entity reference field in the partner-specific hero banner content type, so that I can select which partner(s) a given banner belongs to. This reference is carried over to my view and is applied in a contextual filter so that when a URL query returns a specific partner, the banners associated with that partner are then displayed in the slideshow.

My problem is that the contextual filter is only returning those banners that are explicitly tagged to a given partner. The universal banners are being filtered out and not shown. So for partner2.website.com, only 2A,2B,2C are actually displaying in the slideshow.

I've tried using a views attachment, but the two results (universal and partner-specific) are separated from one another. Same goes for panels. It's important that both the partner-specific and the universal banners are in a single slideshow set.

So then, if a view is set to show both the banner content types, can the contextual filter be set to only affect the partner-specific type and pass all of the universal ones? If so how can I do this?

Alternatively, is there a way to programmatically apply ALL of the partner entity references to the universal banners, so that they are then treated by the contextual filter as if they are tagged client-specific banners? This "ALL" value would have to automatically include new partners, as they are added to the site.

Maybe there's some other solution altogether that has eluded me to this point. Maybe?

I'm working on this in a secured environment, so unfortunately, I'm unable to share links to demonstrate the the site and needs in context. Hopefully my explanation makes enough sense...

Any help is greatly appreciated.