how to filter the documents using lookup columns even after applying key filters in a document library?

Question

Hi,

I have a document library which has bunch of folders, inside folders we have thousands of documents. I have applied "Key Filters" using metadata navigation settings. Now what i would like to do is, i have two lookup(data type) columns. i apply key filters to filter the documents based on some criteria, after this i want to filter based on these two columns. is it possible or is there any other solution. please guide me. would be great if it is a walkthrough or somewhere near to this. Please.....................