If you program them with the free software, there are many possibilities. These radios can be made pretty darn secure for a consumer based radio.
It's not AES256 encryption but the amount of groups one can create is huge making them hard to crack as there is no way to automatically use software to scan through all the possible group codes.
There is a member here whom I forget their username but if you can find that and then search for their posts, he posted some very detailed info on the possibilities as well as the best methods to make them as secure as possible.
I'm not positive but I think the DTR series may offer more group codes over the DLR models. If that is correct, you may not be able to program a DLR model to talk with a DTR model.
I forget the specifics as I set mine to private group codes not long after I purchased a few of them but they are great radios.
A full watt of power at 900 MHz does very well inside steel and cement buildings of several floors tall as well as outdoors.
The only thing I never really cared about them is the analog to digital and back to analog delay the DAC chips cause in the audio.
I don't know if the current models have improved upon that delay.
It's very noticeable if talking with someone within earshot of you.
Other than that minor annoyance, they are great radios if you want something that is darn hard to eavesdrop on by the average person.
Motorola may have something they can follow the signal with but it's not in the public domain if it exists.
Try searching for user @n1das I think he's the person that has experimented a lot with these digital radios from the day the first models were released. Search for his posts in this forum as well as others and you should find a wealth of info from his experimenting with all the possibilities these radios have.
I'm also fairly certain you are limited in the possible settings you can use if you don't use the free CPS software and the correct programming cable and program from the radios menus alone.
The cables do not come with the radio nor does the software but the software is free on Motorola's site and the cable(s) can be found at many places including Amazon and eBay as well as true radio shops that sell Motorola hardware.
I found using the CPS software for both my DLR models and the DTR models made it very easy to create the private groups.
I'd advise to search for the user manuals for the current models as it will have the info you asked for.
