No, Mailbox Assignments need to be removed one at a time with a confirmation after each.
To remove mailbox assignments you can do it one of two ways.
Open the Archive Manager administration website, Select "Mailbox Assignment" on the left side find the user whom you have assigned access to serveral mailboxes and click Select, That will show you all the mailboxes this user has access to. Click the Red X for each mailbox you wish to remove for this user.
Or if you open the Archive Manager administration website, Select "Mailboxs", Search for a mailbox that you have granted access to other people, Click the blue Edit button to the left of the account name.
In the bottom pane you will see all the users that have access to this mailbox. Select the check box and click Remove Access to stop those users from accessing the mailbox.