macky & blackie are right there.
ROFL
"MarkerName" SetMarkerType "Empty" (in init.sqs)
or simply create an "empty" marker, using F6
And when ya want it to pop up again, just use the "Set marker type" command in a trigger/wp/script.
Type may be any of:
"Flag", "Flag1", "Dot", "Destroy", "Start", "End", "Warning",
"Join", "Pickup", "Unknown", "Marker", "Arrow" or any other (addon- ) marker type.
Example:
"MarkerOne" setMarkerType "Arrow"
L8R