Hecto Simul rfid reader multiplex question and timing mat

Hi, I just bought the Hecto simultaneous rfid reader, and the antenna. My purpose is to track start and finishes at races. However I realise UHF works not that reliably when the tag is on a body. Therfore I was looking at having multiple antennas or a UHF mat.

My questions are:
I read in the specs that I can use a multiplex to read multiple antennas. However I can’t find exactly which hardware to use. I am new to both these boards and multiplexers but I have a background in engineering so I should manage.

Second question is, I have been looking at a mat like this UHF RFID floor mat antenna of brand - ITS Chrono
Would that work directly with my hecto? I just need the right adapter for the cable?

Thanks in advance.