From Pluralpedia, the collaborative plurality dictionary
sourcemate (n., adj.)
Applies tosourced headmates

Sourcemate is a term for when two or more introjects share the same source material. This could be, for example, two fictives come form the same media.

Some system members may want to find others from the same source and may do things like a source call in hope to see others form their original source. They may make a post or a announcement of some sort saying they are looking for others that came form their original source.

Other times, members may not even wish to interact with others form the same source due to personal reasons, such as source trauma, not wishing to connect to original source anymore, etc.