ex-/importing only some email accounts

Hi,

how can I export (some) email accounts from a source computer and import some 
of them on a target computer?

One of the email accounts is already set up on the target computer.  Is there a way 
to delete all files and settings related to the account on the target computer before 
importing the accounts there?  Or will I be able to pick which accounts to import 
during the import?

All accounts are IMAP accounts, with no messages stored locally.  The target 
computer has only one account set up and no others.

How would I synchronize the mail filters on both computers when there are 
changes?