Help with optional approval process step

Hello All,

I had a questions on how some people are handling a specific use case in an approval type process. I have 3 groups of people who need to approve something in a linear order. I have accomplished this successfully with no issues, but an additional requirement popped up about notifying a 4th user if an approval is over a specific dollar amount. I use row editing by Assigned column to enforce people approving in order.

Looking at the automations, I can see one for changing a status if a specifc number column hits a threshold, which allows me to set up the initial approval. However, when it comes time for this person to actually approve (they come third), I cannot conditionally set the person in the assigned to because theres no logic right now that checks the numbers field and also assigns to the assigned by.

I need something like this:

If is greater than 5000, and is approved, set team to <3rd optional person>.

How are you guys handling a scenario like this? Hope I explained it well, I can show screenshots for added context.