multiple audio fx on one audio track?

Hello Again,

I can't seem to figure out how to apply multiple audio fx in one audio track. I have a 48min audio track, and during the track I need to apply different kinds of noise reduction etc, I don't want the effect applied to the entire track, just the section I want. Now on video, it's obvious as you have a green + next to each little clip and can change the fx on each seperate clip, when I go to an audio track and pick an fx, it applies it to the entire track. I've looked into automation etc and these seem to be for mute,pan and volume.