In addition to any contacts you uploaded to a segment or added via Shared List, you will want to add any subscribers that have opted into your Email Groups. To do this, add a dynamic filter to your segment.

1. Open your segment by going to Audience > Segments (or create a new segment).
2. Click the + button in the left hand panel of the page:

3. On the right side of the page, you'll see a list of filter criteria:

4. Scroll down and select Subscribed to Groups:

5. Double-click the light blue bar on the canvas that says Subscribed to Groups:

6. A pop-up window will appear. 
   1. In the first dropdown menu, search for the Email Group you want to select. 
   2. Click Add to ensure the Group appears in the list.
   3. Ensure the second dropdown says as of now, not a date.

7. Click the Save button to save your changes and refresh your Segment's contact count.

Now your Segment will include any subscribers that were not on your list upload!

Note: You do not need to add a filter to remove unsubscribes. Eloqua will automatically remove any contacts who have unsubscribed from the Email Group attached to your Email.