In order to solve this problem, I need to know the actual specification for the TCP messages that we can expect to receive. We need to look at all possible messages, not just a single example at one time.
What are the possible values for the ID byte?
What are the possible values for the gain byte?
What do all the other bytes mean, and can they change, or will they always remain the same?
If we know this we can solve the problem. Otherwise we are just fooling around for fun...
My main concern now is, how often do these "update" messages arrive? If you are using 5 tags and each one is sending a message every 5 seconds, VC will be constantly dealing with these messages which will most likely interfere with the normal operation of the program. In that case you should really find an alternative solution, such as a python script that is running on its own thread, which only interrupts the main program when something significant has happened, such as someone arriving, or someone leaving.
Another option would be to have a second VC running, only for this purpose. It could send updates to your regular VC.