The properties specify identifiers of a receiver and a group of receivers.
property GUIDTo: String;
property GUIDGroup: String;
If UseGUID=False, GUIDTo and GUIDGroup are ignored.
If the receiver's GUIDMy is empty, it accepts data from senders having any value of GUIDTo (empty or not).
If the receiver's GUIDMy is assigned, it accepts data only from senders having the same value of GUIDTo.
GUIDGroup is ignored.
If GUIDTo is not empty, it identifies the client to send data to: the server sends data from this sender to the specified client only.
Otherwise, if GUIDGroup is not empty, the server sends data from this sender to clients belonging to the group identified by GUIDGroup.
Otherwise, the sender sends data to default receivers. If this list is empty, data go to nowhere.
'' (empty string)