It's not like (or compatible) with Hytera's pseudo trunk standards, but Kenwood NX5xxx series radios (and probably more) with DMR have a feature available on the subscriber radio that will do about the same thing more simply. In the channel settings there is the ability to select Time Slot 1, 2, or AUTO... and according t the help file, "If "Auto" is configured in this function, the transceiver switches to the other slot to try to transmit when one of the slots is busy."
The radio monitors both slots to catch info and will receive and transmit on the slot it hears it on. Likewise, if a slot is occupied, it will use the other... so as long as all the radios on the system are Kenwood and setup this way, you have, by definition, a sort of pseudo trunking. I'm playing around with this feature on my radios and DMR repeater right now.
-Josh