EQ portions of a clip in Soundtrack

Sorry about the double post.

I would like to be able to apply EQ effects to portions of an audio file and just apply the effect to that one portion. I noticed that when I selected a portion of the file and set the EQ parameters, the EQ affected the entire file. I need to EQ different portions of the entire file. How do I affect just one portion at a time? Thanks.

GlennC