Network latency might be an issue if you were relying on anything other than an LTE network.
Packet prioritization (QOS) would be the way to do this, but the networks aren't going to pass that.
If your business was running it's own WiFi network and you could get the network wonks to give your traffic higher prioritization within your own network, that would be a pretty good solution.
However, I'm guessing this isn't a mission critical application.
The other thing I'd be concerned about is the quality of these Chinese radios. Looking at the ones that have shown up the last few years, I'd not want to rely on one for anything where my life, or someone else's, depended on it. Fine for amateur/hobby use, but nothing more.
Might be worth checking in to what your mobile phone network can supply. Many of the networks will pass Push To Talk traffic over their network.