Unfortunately there does not seem to be an option to stop the numbering at a certain point.
However there is an option to label components (i.e. stair treads).
I just tried quickly in a default 25 template and it seems it would work, but I have no favourite set up for the tread step index.
I am not sure if it is a section only thing or if it will work in plan as well.
It seems it will label all of the treads but you can delete the ones you don't want.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10