many-to-many relationships between model using different db

Hello to all
  I am finding out ways to set many-to-many relationships between my two
models with each model belonging to a separate database.
for e.g

1. I have a "User" Model belonging to "database_1"
2. I have a "Project" Model which belongs to "database_2"

Apparently there is many-to-many relationship between these two models.
Had the Models been belonging to same databases my job would have been
much easier I would either use hbtm or has_many_through associations for
but with each models belonging to there respective databases.I kind of
got stuck with it
Any Suggestion

Thank Anyway

Are you able to access both the databases in your single application?.
If so, what connection settings you have?.