If you can handle lots of reflections, you can just short a bunch of connectors together. The return loss will be about as bad as the insertion loss if you had used a resistor divider.
Otherwise, I don't think there exists a solution for N > 2 ports where all share evenly, with no reflection. And the case for N = 2 is trivial (just a union connector).
After all, in a simple one-to-all connection, "all" includes "self"!
If you want it for "all besides self", on all ports, you'll have a harder time. I suspect one isn't possible without circulators (which means it would have to be done in the GHz, where those are available). It wouldn't be cheap.
Remember that an RF network requires matched loads on each port, otherwise the load seen at other ports will be different (reflection from one port causes reflection on the others). So it still won't be like a hub in the network sense, where up to N ports can be in use.
I think hubs with rx/tx integrated are more common, which also has the benefit of decoding, cleaning up and encoding the signal anew, and as long as you're in there looking at the data, you can put routing, inspection, etc. on it too, saving bandwidth as well.
Tim