Query_posts using multiple custom values (meta_value)

Hola!

I’ve been trying to generate a query_post call to get a list of posts that have 2 or more meta_values, but it’s been impossible.

Basically, let’s say that all posts have a custom field called “age”.. and I want to get (using query_posts function) all posts which have age=22 and age=25.

I’ve tried:
query_posts(‘meta_key=age&meta_value=22&meta_key=age&meta_value=25’)
query_posts(‘meta_key=age&meta_value=22&meta_value=25’)

but, obviously, I’ve got no success… Anyone knows how to solve this?