Surround an arbitrary amount of words with any string after you've already written them.
Add dictionary entries like these:
"SPREPBS": "{:retro_surround:1:(:)}"
"SPREPBS/SPREPBS": "{:retro_surround:2:(:)}"
"SPREPBS/SPREPBS/SPREPBS": "{:retro_surround:3:(:)}"
and that's it!