complicated association finder query

Hi Guys,

If I may explain my problem with an example.

Models:

Monitor (computer monitors)
has_many :features

Feature:
name = [big, small, black, white]

I want to find a Monitor that is BOTH white and big.

My first shot at this:
find(:all, :include => :features, :conditions => ["name IN ('white',
'big')" )

But this query will find Monitors that's EITHER white or big.

I can't figure this out. Can anyone help at all?

Xin