I'm not sure what you mean by that. There's multiple accounts to invite. Do you mean a shared group?
I actually just tested creating a google group now, but indeed you cannot invite a group to a shared photo album.
Creating multiple shared albums, and sharing each album individually, manually, every single time, is super cumbersome. Plus I don't think the other users see the list of shared albums anywhere.
A huge shame given how great of a photo gallery app Google Photos is.