Split (Analysis)—ArcGIS Pro | Documentation contains links to
Introduction to attribute domains—ArcGIS Pro | Documentation
which may provide some information if you are referring to how split policies are handled
What is the goal? Relationship class split policy might be what you're looking for. This article describes what you can do with it: https://pro.arcgis.com/en/pro-app/latest/help/data/relationships/relationship-class-split-policy.htm