I am trying to create an audit document table whereas options are selected from a drop-down selection, which then allows for 3 options in the following box in the table.

There is 7 selections in the intial drop-down (e.g. Oppourtunity), which the requires 3-4 'outcomes' per oppourtunity in the second drop-down
Each 'outcome' differs dependent on the oppourtunity.

For clarity
Oppourtunity A - Allows outcome 1,2 & 3
Oppourtunity B- Allows outcome 4, 5 & 6
So there is 7 oppourtunities, and 21 outcomes total in the dropdowns

I have the dropdowns set but am struggling to get the cascade and flow-through from each dropdown list.
Im sure its pretty basic

Thanks