How to get a table to match the number of rows, and row order, of a parent table

I have a table that holds all of the expense types that I want to track. Things like gas, electricity, ext. Then I have separate tables where the first column is linked to that table so the rows are selectable only to the rows existing within the parent table. This is really convenient, and I like it. I can see all of the expenses and the rows auto update depending on which expense I select, and I can hide the other expenses through the drop down. Great.

I want to add another level to this though. When I add a row the parent table, a new expense I want to track, I want to other tables to add that row as well, and to add the formula's from the other columns within their tables. Currently if I add a row to the parent table, I have to go to the other tables, copy and insert the row and select the new expense. Which is really not that difficult, but this would add another layer of convenience.