[COD 1.1] How to make a .pk3 used only on my server ?

[raphael]

Hello

There is a .pk3 that replaces bullet traces colors.

I want to put it in my server, if I put the pk3 in my main server folder, then clients will download it to their main folder and then it will be run on all servers. (i guess)

Do you know how to make it run only on mine ?

I try to learn modding

EDIT:

Do I have to use the "fs_game" command ?
I think that this command is associated to a folder in game's folder
Any info would be really appreciated