It's not possible. However, this doesn't forbid you to join tables from
different databases in your SELECT queries. Unless you wanted to set up a
relationship with Cascade Delete or Cascade Update; you lose nothing by not
etablishing any explicit relationship but don't forget to etablish the
proper indexes on the foreign keys fields for performance reason.
--
Sylvain Lafontaine, ing.
MVP - Windows Live Platform
Email: sylvain2009 sylvainlafontaine com (fill the blanks, no spam please)
Independent consultant and remote programming for Access and SQL-Server
(French)