Is it possible to have three diffferent Blackberry devices each one of them configured to access to the same Exchange account (mail, calendar, contacts) via BES?
If I read an email on a BB, the message should be flagged as read on other two, if I delete or move a message on a device or if I modify/create a calendar entry, I must see the same changes on all the devices.
Now the user has 3 BB devices configured with 3 different accounts with BES and Lotus Domino. A feature of Domino keeps the three accounts synchronized, but I did not find such a feature on Exchange 2010
Update: Since BB does not support multiple device accessing the same email, the only solution by now seems to create different accounts and synch them with Exchange Sync http://www.codetwo.com/exchange-folder-sync/
This is not possible. BES stores hidden device information such as PIN in your mailbox, activating a second blackberry will override the hidden information from the first device.
Your only options would be to setup desktop syncing, in which the devices would sync, but not wirelessly. Alternatively you could go with less features and sync via smtp, or use mailbox forwarding to sync inbound messages between the groups. Unfortunately this will not give the features you describe in your question.
It can't be done that I'm aware of.
Also, your question contradicts itself. You say that you want 3 BB's to access one Exchange account but then you state that you have 3 BB's with 3 different Lotus Domino accounts.
It is not possible because everytime when user's account activated on the BES. Device and RIm infrastructure send a new ETP.DAT attachment mail to verify the mailbox. which is having all the device information such as device imei, pin etc. if same account already activated on the other device and we tried to activate same on second new device than BES replace the all the device info into the BES configuration DataBase and activated email ID into new device, after that Mail Flow in previous device is not happening and BES delivered the data to new device on the basis of PIN basis which stored into BES databases.