Team/Channel for Deal Desk support

[PGarfunkel]

I run a 24x5 Deal Desk team.
Similar to support, we have rotating shifts.
I currently have a ‘bat-phone’ that rings simultaneously at all team members desk phones like you would with a support team.

As we adopt Microsoft Teams more and are starting to move away from Telephony I’d like to implement something similar within Team (so I can rid of telephony completely).
I’m unable, however, to setup similar functionality in Teams:

How can a random user call into a Channel (or a Team) without being a permanent member of it?
Or is the solution perhaps to leverage some App to be connected to Teams via plugin?

Thoughts?
It sounds like it should be a no brainer to do this in 2019.

[#2]

Teams was designed to work and collaborate as Teams initially, not be setup to run a support desk.
If you wanted a call in number it would have to be a Phone System call queue not related to the Team itself.
If you mean VoIP call in, as far as I know there isn't really any options there.

There are some integration points for Teams but it links to other real support desk type systems such as ZenDesk etc. But it won't link calling in any way to my knowledge.

I'm about to go down the path of figuring out a way to generate support requests across the board into Zendesk from an @ mention, but thinking of utilizing a webhook of some kind for this.

Be curious to see if this is even possible, but to my knowledge it's not right now.

[#3]

@PGarfunkel 

It is just an idea but you can setup an O365 Account for example Support Desk and in the Teams Client for the Support desk user you can setup a call group with your other Support users and say ring all at the same time or in the order you have set up the group.

Cheers

[#4]

@Pete32 thanks but have to say I do not fully follow.

Not sure how a 'Call Group' is setup in Teams. Will try to fiddle with this...

[#5]

@Pete32 found it; but turns out one needs Enterprise Voice license for this (which looks like I do not)

https://support.office.com/en-us/article/call-forwarding-call-groups-and-simultaneous-ring-in-teams-...

Will chase my IT manager - thanks