From what I understand this feature was NOT in the original DOS release.
Are there any mods that mod thet original dos version to add hotkey grouping for units?
can you please explain a bit further what do you refer to grouping units ?
if you refer to change the hotkeys for units in DOS version, i think may be but haven't checked yet.
EDIT:
nevermind, I tried to incorporate customized hotkeys to one of my mods that is for DOS version and couldn't.
In case you would like to check out a MOD for the DOS version though, there's my DAIFE mod. Harder difficulty and some audio/visual enhancements. I hope it helps you in case of being interested:
https://gamebanana.com/mods/288680
