diff --git a/ghost.lua b/ghost.lua
index eb39b0b..e24111a 100644
--- a/ghost.lua
+++ b/ghost.lua
@@ -406,6 +406,10 @@ Server = {
 
 		transmitters = {},
 		callback = function(cmd, handle)
+			if handle.transmitters[cmd] then
+				return
+			end
+
 			local mapindex = Index:getMap(gamemap, mapChecksum(gamemap))
 			local header = assert(mapindex[tonumber(cmd)])
 			local data = Ghost.read(header, Ghost.stringReader)