Two tenants, two domains, two companies, one shared calendar ... how?

[thecomputerguy]

Company A just bought Company B.

I've been granting access to their primary team in Teams as guests which has been working fine but they want a single shared calendar.

I think my options basically are:

1.) Shared Mailbox
2.) Groups in Outlook
3.) Public Folders

4.) Teams Calendar?
5.) Sharepoint Site

1, 2, and 3 all require everyone to be on the same tenant, or have a mailbox on that tenant so that is probably out.

4.) I've heard the calendar app you can add to teams doesn't really function as intended as a shared calendar. I've read online that it functions as a teams calendar scheduling tool. A lot of complains about how when an event is create in the Teams Calendar app everyone gets emailed with an invitation to the event. Probably no go.

5.) The most cumbersome and least likely to be used, since people have to go out of their way and into a SharePoint site to get to it, but probably the best option we have?

 

[callthatgirl]

Setup a Teams Channel calendar if it's for Teams mostly, this will not synch with their Outlook.
I don't like the shared mbx calendar, most of my clients just buy 1 mbx for this so everyone can edit and use on many devices.

 

[YeOldeStonecat]

You can create the 365 Group...which creates the calendar which will show up in users Outlook automatically, and then upgrade that 365 group to a Team. Or...if you already create the Team (thus the calendar won't show up), you can run a powershell to "unhide" the calendar. Since they're already setup to use that Team..I'd probably take that approach.

That cool "Channel Calendar" add-on for Teams...I don't think they added working with external users yet.

The shared calendars are easy to add to the Outlook app for internal users, but I don't think for external people it would work.

 

[trevm999]

I'm 99% sure you can connect to a SharePoint calendar in the Outlook Desktop calendar. I can't remember if I ever tries it multi tenant, but I think it would work.