How do you use Family Sharing to effectively merge multiple Apple IDs? My wife and I have separate Apple IDs. To simplify (!) things a while ago we both started using a third ID.  

Now with Family Sharing we can each access the other's purchases.

So I set myself up as the family organizer, invited Laura, and invited the 3rd account.

Well to accept the invitation for the third account, I would have to sign out of iCloud, loosing a bunch of data, or possibly having merge problems later.  

The invitation has to be opened in Mail. I try not to use Mail. I certainly didn't want to not only sign out of iCloud, but also configure yet another account on Mail.  (The third Apple ID forwards to both of us.)

What to do?
.The answer turned out to be only slightly convoluted.


Set up a new user on my mac, tempaccount.
Login as new user.
Use 3rd id as my icloud login.
Set up my gmail account as the Mail account.  (Since I don't intend to send email with this account on a regular basis, I don't really care if Mail.app gets confused.
Find the email forwarded from 3rd id to my gmail account.
Click and accept.


With luck this may help other people in similar circumstances.