title: AWS Codepipeline with multiple input sources. Only want to trigger it with one of them
body: <p>Anyone run into this issue where you have a Codepipeline with 2 input sources. Say, two s3 buckets, and you want to run the buildspec off the second input source, but you only want to trigger the pipeline on the 1st input source?  I don't want it to trigger if there are updates on the 2nd bucket.</p>
  <p>Anyway I can prevent that? Or even prevent anything from being run in the buildspec if the 2nd bucket gets updated?</p>