More than two users can edit the shared document at the same time.
Click on the 'Groups' link text to display 'Group List' page.
Input a name then click on the 'Add new group' button to add a new group.
Click on the new group name link text to display 'Group Properties' page.
Click on the 'Group member' link text to display 'Group Members' page.
Input a username or email address who you wish to share documents with, then click on the 'Add new member' button to add a new member.
Check 'Read' and 'Write' in the new member.
Click on the 'Dynamic Draw Web' link text to back to the top page.
Click on a file name link text which you wish to share, to display 'File Properties' page.
Click on the 'Groups file belongs to' link text to display 'Groups File belongs to' page.
Check the added group.