In editor, place a player, name it;
place a backpack ("B_AssaultPack_Kerry" in this example);
place a mortar unit, name it;
place a module requester, name it (say request);
place a module provider artillery, name it (say arty);
synchronize request to player and arty to mortar, let unsynchronized arty and request as scriptable sync.
in init.sqf (or elsewhere), add this loop:
player spawn {
_unit = _this;
while {true} do {
sleep 2;
waituntil {sleep 2; (backpack _unit == "B_AssaultPack_Kerry")};
if !( request in synchronizedObjects arty) then {
arty synchronizeObjectsAdd [request];
hint "support added";
};
waituntil {sleep 2; (backpack _unit != "B_AssaultPack_Kerry")};
request synchronizeObjectsRemove [arty];
hint "support removed";
};
};
The hints are toggling while taking/dropping this backpack but you can get the support only the first time you take the backpack.