Bibliography sort order, why do I need to do this manually

My PI pointed out to me that our bibliographies are not sorted by anything other than order of appearance.  While this is great because most bibliographies are ordered based on the location they are used in the article, they also should be organized within these subgroups.  The problem is there is no obvious/covenient way to do this as far as I can tell, which means every time I want to add a citation I have to make sure I’m inserting it based on chronological order.

For example when submitting for AJOC:

For my very first citations I insert Roberts 2008, Johnson 2007, Gomez 2010.  

Then in a following paragraph I insert Black 2009, Roberts 2008, Marcel 2007.

As it works now my bibliography it looks like this:

  1. Roberts 2008

  2. Johnson 2007

  3. Gomez 2010

  4. Black, 2009

  5. Marcel, 2007

When for every journal they want it formatted like this:

  1. Johnson 2007

  2. Roberts 2008

  3. Gomez 2010

  4. Marcel, 2007

  5. Black, 2009

Is there a way to modify styles to sort properly?  This seems like a major oversight as it is standard practice.

Please help, let me know if I wasn’t clear it what I am trying to do.