Help| Sync' boolean variable (Friendly Fire)

so i'm trying to make friendly fire option, that the hoster of the server can choose between 2 buttons "Enable","Disable". if he chose enable - friendlyfire = true; if he chose disable - friendlyfire = false;

but i need to send the Choice of the hoster to every player who connect to the server (as client). i mean .... if the "friendlyfire" variable in the hoster set to true, then the "friendlyfire" variable of every player who connect to the server, will set to true too.

and if if the "friendlyfire" variable in the hoster set to false, then the "friendlyfire" variable of every player who connect to the server, will set to false too.

i triend but without any success, and i need your help.