iOS Photo Shuffle - can't feature two or more people

I have thousands of pictures of my partner and I, and I currently have my iPhone lock screen set to feature pictures of just my partner.

However, I really want to feature pictures where it's both of us in the same picture, but when selecting which people to feature, I can only choose individuals rather than groups.

I'm assuming the obvious workaround would be to create a new album with all these photos and then use that as a source for my wallpaper. But the thing I love about photo shuffle is that I can include pictures of pets, cityscapes and nature that are in my library. These of course will update as I take more photos and add photos to my library, and are interspersed with the pictures of my partner (so it's not just all pictures of them).

Having to continually add new pictures to an album would be somewhat of a chore and takes away the point of Photo Shuffle being a minimal-interference wallpaper tool.

Maybe it's just that the Photo Shuffle feature doesn't allow for this yet (in which case, please add this Apple!), but is there any other workaround that wouldn't require me making a new album or anything like that?