Clustered Column Bar Graph - Change Groups/Pairs

I'm using Excel 2013.
In the attached graph, I would like to change the groups or pairs. Currently, 2014 is one group and 2015 another group. I would like to try it with four groups - ID, MH, SA, and NC. It would look the same, but ID 2014 and ID 2015 would be a pair with the same color. The next pair would be MH 2014 and MH 2015. Then the same with the next two. Each pair would have a different color. I know I'm missing something simple. Thanks for any assistance or helpful links.