How many mailboxes can you share with 1 user?
When i share 1 mailbox from userZ to userA there is no problem, when i share a second mailbox from userY to userA then i receive a message that the "mailbox is alredy shared". When i share a map from userY and userZ to userA then there is no problem.
So, maps from several users can be shared to 1 user, but how many "mailboxes" (the default incomming map) can be shared to 1 user?