Hi Martin, indeed you can connect up to 3 FloJack Mini antennas in parallel.  To do so you will need to get some standard 2.54mm receptacles.  See the diagram below on how to wire everything up:

With a soldering iron and some thin wire you should be able to put this together in 10mins.  You can also create extender cables in between the receptacle and NFC BandAid, but remember to keep the overall length of the extender to under 3 feet.  Here is a video of a similar setup I put together recently for another customer.

Let me know how it goes.  Would love to see pictures of your build as well.