here in my location the mental health community use the term "host" to designate the person that is diagnosed with DID (person born to the body the day they are born from their mother. ) and the terms "alter" "parts" "insiders are used interchangeably to designate the alternate personalities.

for me I knew I was the host because I was the one diagnosed. I was the one born to this body and I was the one that had the symptoms of dissociation and time loss (which designates switching into alters here where I live)

like I said before alters are anything that is needed to ensure the host survives. so how ever your system is made up / comprised of / or works is the way its supposed to work for you. so yes how ever you are is possible. if it wasnt you wouldnt be the way you are.