Digital Audio Editor -- to remove background noise

I have three distinct audio recordings uploaded to Dropbox that range from half an hour long to 2 hours long. Each recording has unique crowded restaurant background noise that makes the conversation difficult to hear. I believe an expert audio editor could be able to identify and isolate the background noise to remove it from the recordings so that the conversation is heard better. I believe once isolated it's easy to remove from the entire recording, thus I don't believe this requires scrubbing a two hour tape -- rather it requires isolating the noise pitches to remove and then removing them entirely. Hopefully this makes sense. Short version: I want the background noise gone so the conversation is more easily listened to. [login to view URL]