There's some range of systems that call themselves "Median" systems — they're in the wide grey areas between plurality and singularity, and can determine whether they want to identify as plural (of course).
A median system generally speaking has 1 front and 1 or more internal parts/people. They can converse, have concurrent differences of opinion. The internal folk may exert passive influence. To set them apart from aspected singulars or subsystems, the individuals may all show up to meetings just as themselves (unless also aspected).
Some medians are more "vague" inside, not as clearly delineated, but generally there's a more "many-ness" sense. Still there's a lot of grey between types of plurality.
System types all exist in a big grey continuum and can get to a point of "difference" where they're clearly different from another system type, and then the community attempts to tag it with labels or can put words on the differences. But every plural system is unique. So are age sliders aspects or are they plural or median subsystems full of distinct individuals? That's kinda up to the system in question to figure out. That's part of the selves-discovery process.