query_posts with different database

Hello and thanks for reading this. I have two blogs installed using the same database, one with $table_prefix = ‘wp1_’ and the other with $table_prefix = ‘wp2_’. What I want to do is displaying posts from the second blog (wp2) on the main page of the first blog (wp1), but when I use query_posts it always takes posts from the current database (wp1). How can I use query_posts to get posts from other table in database? 10x.