Automatic generate meta key options

Hi,

First of all, great plugin! It works fantastic.

The only question i have is:
Is it possible to automatic generate the options of a meta key?

Example:
I have 300 posts about different products. Every post has a custom field with a meta key “brand”. There are 34 different brands in the database.

It would be awesome if i can say by the options (drop-down menu content) of the meta key “brand”:
“All brands in the meta key brand”. So the dropdown menu will be:
Brand 1
Brand 2
Brand 3.. etc.

Instead of typing all brands by myself ( brand 1 | brand 2 | brand 3 | etc.)

Thanks in advance!

http://wordpress.org/extend/plugins/wp-query-search-filter/