I could be wrong, but I think a dongle is merely a Bluetooth receiver (versus, say Logitech, where a dongle has an identity) unless these specific dongles work differently. A jumps slot on the TB has a Bluetooth id it projects to the world, and an associated keymap it uses to translate key presses into keys sent as that Bluetooth id.
When a TB is id 1, I think there's nothing to prevent three different Bluetooth receiving devices (a phone, an iPad, a Mac mini) from recognizing the same id. I'm guessing handshaking prevents multiple receivers from connecting at the same time, but if two Macs are at different locations, I think they'll both work with the same id.
Alternatively, if the computers are such that you need the dongle to handle all Bluetooth everything and just present as usb, you do get 6 jumps slots. More configurations than that... I guess that's a tricky world to live in, and probably not super prevalent, and would require some software features to enable. Having said that, Waytools doesn't seem to shy away from adding features when they make sense. Ask them via the app, and see what they say!