Zello is not to be cross-linked to BrandMeister in any way.
All of the US Master server owners decided among themselves that they do not want any part in facilitating other amateur radio operators to knowingly or unknowingly break the rules that the FCC have made for us to abide by, these are the same rules that you sign to agree to after you successfully pass an amateur radio examination.But the reason people are doing so, is because they want access to the network in a more logical way than we have now. So lets review.
Presently the only thing that ensures the voice traffic is from a ham is that traffic be AMBE encoded, as that is how its natively transported anyway. This leaves you with two traditional options;
1.) Use an transparent RF "hotspot" to take the native AMBE traffic from your HT and put it on the internet. These are generally Part 15/10 mW transmitters, to provide "in-house" coverage
2.) Use an AMBE hardware dongle to do the encoding.
The problems are that the first option is a lot of hardware to haul around to effectively talk ~50 feet into a radio. And the cost.
The problem with second option is mostly cost and a lack of wide support for doing so, especially with mobile devices. So that is why people are bridging to Zello.
In the near future software AMBE will be widely doable. The "unverified ham origin" problem will metastasize as software AMBE becomes easier. So WE NEED to incorporate automatic authentication into this somehow.
Right now we have security by obscurity, as the traffic is merely in a strange non-standard AMBE format. BrandMeister seems okay with cross linking to Allstar. Allstar, like EchoLink, IRLP, and the other "ham" VOIP systems manually verify that you are a ham.
That could be and probably should be automated. You could be uploading your LoTW (Log Book of the World) digital P12 certificate to their sites to verify that you are a ham. (The LoTW verification process sends a post card to your FCC address, and Then issues you the digital P12 certificate)
But we need to get all these ham VOIP network operators to implement that. From there, you can use the IAXRPT or Zoiper apps to talk into the Allstar networks and thus DMR and other digital networks.. Or the Echolink app, etc.
It would be ideal if your allstarlink.org account could be verified automatically this way. And a unique SIP credentials would be auto-generated. so you can use normal Apps to connect to their server directly. From there and IVR menu of options could exist. Like "Press 1 for Talkgroup X" etc.
These concepts could also be something for the newer hamshack hotline folks to explore.