It could probably be done by actually doing a replacement. Make all but the first group in each route non-capturing, and then replace it with something like " $

It could probably be done by actually doing a replacement. Make all but the first group in each route non-capturing, and then replace it with something like " $1 $2 $3 .... $n", and count the spaces. You'd have to then do another regex just for that route with all groups capturing. So for 100 routes with 9 placeholders each you would do 1 regex replace that worst-case had to populate 100 groups, and then a second replace for the identified route to populate 9 capturing groups. Does that make sense?