Yes this is definitely possible,
Assuming two tables T1, T2 , T1 is related to T2 via field KEY
you will add an attribute rule on T1 and you can have it trigger on update so that it makes an edit to T2 and update the related feature on T1 (find the parent feature by querying T1.KEY = $feature.KEY ..
Here is a blog detailing this
Advanced Attribute Rules – Editing features on another class with attribute rules
You can restrict the attribute rule to execute only if a certain field has been updated by using $originalFeature