my dissociative type alters all came with their own sense of agency. (sense of agency is a new diagnostic criteria since 2013, its just a new word for saying that all dissociative type alters have their own jobs, purpose, reason why they were created, how much control they have .... lots of things this new phrase covers)

to find out what each of my alters sense of agency was all my treatment provider and I had to do was to keep a journal documenting when I had my dissociative symptoms, ...

example by keeping a dissociation journal I discovered that when I felt numb, spaced out and disconnected because I was triggered by rain storms, the alter rainy would take control and handle this trigger by getting home, wet clothing changed a warm cup of hot chocolate and a sandwich,

evidence of this is my dissociation symptoms, wet clothing in the clothes hamper, pb&jelly and bread on the counter, empty hot chocolate wrapper and dirty mug on counter.

so now we knew what Rainys sense of agency was... in other words her purpose was to handle the trigger rain storms, get everyone home safe and dry and a snack.

my suggestion maybe you can start keeping a journal documenting times when you all switch and what the triggers are that is making you dissociate (switch) and which alter belongs to which trigger that they handle.