This is absolutely possible.
Instead of specifying the field for the rule and returning a value, you leave the field empty and return a dictionary. This dictionary has to have a defined structure, which you can find here:
https://pro.arcgis.com/en/pro-app/latest/help/data/geodatabases/overview/attribute-rule-dictionary-k...
A simple example:
// Calculation Attribute Rule
// field: empty
// triggers: insert
return {
edit: [
{className: "OtherTable",
adds: [
{attributes: {TextField: "Value", IntegerField: 5}}
]
}
]
}
EDIT: And you can do lots of other things, too. A few examples are listed in this blog post:
Advanced Attribute Rules - Editing features on another class with attribute rules (esri.com)
Have a great day!
Johannes