It is possible in the event library, but I would suggest that you do it in an app called MPEG Streamclip. It will be much faster and easier to do it using MPEG Streamclip.
Download MPEG Streamclip here.
Drag your large file into MPEG Streamclip.
Now, set your playhead to the beginning of the first event, and type i for in point. move the playhead to the end of this clips, and type o for out point. Then, use FILE/EXPORT TO QUICKTIME. Choose Apple Intermediate Codec as your codec. (Note: if your original clips are in DV, you may wish to stick with DV. Otherwise use Apple Intermediate Codec, and don't change any of the settings. Give it a name and location. You can import this into an iMovie Event using FILE/IMPORT MOVIE in iMovie.
Repeat this until you have all the clips you need.