Workaround for inviting external users to site-level groups in office365

Question

I've got a site collection where each subsite requires their own unique permission groups (Let's call them siteVisitors, siteMembers and siteOwners) Users in the siteMembers and siteVisitors groups should only have access to that particular site. People in the siteOwners group should be able to use the "Share this site" feature to invite external users to the siteMembers or siteVisitors groups.

I've changed the settings for each site so that the site's siteVisitors and siteMembers groups are the default groups, thus all invitations are sent to those groups. (this setting can be accessed 'via /_layouts/permsetup.aspx' )

The problem is that this solution doesn't work in office365: -According to staff at the office365 support forum, it basically shouldn't be possible to invite external users to any other groups than the site-collection level groups Visitors and Members, which are created by default when creating a new site-collection. This has to do with the features that control whether Sharing to External users is enabled or not is somehow connected to those default groups.

I've found that it IS possible to invite external users to ANY group - allthough it's random whether it succeeds or fails (about 50% of the time you get an error when pressing the Send button in the invitation dialog)

A. Would be nice to get some confirmation from you guys - in o365, is it possible to invite external users to other groups than the site-collection Visitors and Members groups?

B. If it truly does not work I need some help redesigning my solution I guess I'll have to change it so that all users are only invited to the site-collection level Visitors or Members groups. AFTER they join, they must be moved to the correct site-level group (the siteMembers or siteVisitors group on a particular site). Would like this move to be made automatically. Is that possible? Is there something like a UserAdded event reciever where you can check from which site a user was added ?

Answer 1

As far as I experienced you can do it - but more manually:
You have to set the group as default/ standard group and then you can invite people into.

As you see, this goes crazy if you have multiple invites to different groups. So it could be an option to pick the external users out of the generic group and sort them one by one into their specific group. You need to keep an eye on which subsites should be visible to everybody in navigation bars.

That has three problems:

• To invite external users, you must be site collection administrator, Full Control on target subsite is to less.

• You can handle external users inside SharePoint only after they accepted their invitation.

• And it requires that external users have something like read permission on root collection site to avoid the user experience "access denied".

My way to go is creating a website collection for each company/ project with the same target group and put them into the generic groups. Give them specific rights (for group) and/ or separate them after first contact.