Laying Over/Under across multiple markets

I'm looking for some help with developing a trigger than can work in a similar way to the lay-total-goals trigger that already exists, but across Over / Under goal markets

I want to be able to lay on the Over x.5, tracking my losses. If I lose the bet I can then lay on the next Over x.5 market for the same match.

I've been able to get this working if I open all of the Over / Under markets for a match, but I'd like to be able to run this over a number of matches (market_parent) at the same time - this means tracking the total loss at a parent level rather than an individual market and this is where I'm getting stuck.

Please let me know if you need any more details

I've attached my attempt so far