So what happened was that the phone making the page was the one being barged in on because it's also part of the multicast group. As such it was even worse since it put the page onto hold music.
The numbers relate to which multicast page groups and below are allowed to barge. Setting to 0 means none. Since you only likely have one multicast page group and don't want barge 0 is the correct setting.
However if you want to have multiple page groups and allow the first group for emergencies to barge and the others (group 2 and higher) that are lower priorities to not barge that's where the numbers fit in. In that case you set the paging barge to 1.
From what I have seen with 3CX's approach to their Yealink template and their provisionable options, they take the road of the Yealink defaults are their defaults as much as possible and the provisionable options that 3CX gives you allow you to change away from the default. As such since Yealink's default for paging barge is not 0 and 3CX doesn't allow this to be adjusted through the management console this is what you are left with without resorting to custom templates. Thankfully the more stupid Yealink defaults are adjustable through 3CX such as the option to blink the message waiting light on a missed call. Although as you can see even for that option, 3CX leaves it as Yealink's default but allows you to move to a proper setting of Voicemail only through the management console without resorting to custom templates.
3CX's approach to sticking with Yealink's default options make sense. They could set different defaults but that would cause people on the other side of the fence to complain. In this case people who want paging barge would be upset if the option were to be changed.
