Create A Dynamic Linked Table That Will Add Row(s) When A Row Is Added To The Parent Table

I have two tables for budgeting. One table is for categorizing, the other, or a separate worksheet is to enter monthly budgets. Both tables have a "Sub Category Column. I would like to link the "Sub Category" column so that when I enter a new category in the parent "Category" table, a row is inserted in the "Budget" table in the same order. It should shift all rows down and create a space to enter a budget for the new category.

Please let me know if you need more clarification. Any help or insight is appreciated.

Thanks.