How to use the results from OR syntax in substitute part of regexp?

I have symbols like the following ones

"live_set tracks 113 devices 22 chains 7 devices 8"

"live_set tracks 66"

"live_set master_track devices 4"

"live_set tracks 45 devices 22 chains 7 devices 18 chains 0 devices 7 return_chain 2"

So they can vary in length and the pattern is not always 'word number word number etc.'.

I want to add leading zeros so all numbers are 3 or 4 digits long.

I used the OR syntax to find numbers of different lengths, but how do I use these to add the correct number of zeros in the Substitute?