static objects are local to all, so if you use a specific client side script or server script to damage one, all should see the results
as for the waypoint question, this is local to the group
if the group leader is a player then the group is local to the player
not sure what happens if the group leader is AI and a player is in the group,
in this case the waypoint is definiotely local to the player but not sure if it is local to the server too