replace:
if(six_isServer)then
{
	// Runs on Server and ServerClient (Ingame Server Hosting by Client)

};


with:

if(six_isServer)then
{
	// Runs on Server and ServerClient (Ingame Server Hosting by Client)

}else{
	{deleteMarkerLocal _x} forEach ["NameOfMarker1YouWishNotDisplayed","NameOfMarker2YouWishNotDisplayed","NameOfMarker3YouWishNotDisplayed"];
};