Excel analysis of data

I have 2 sets of data (attached), one is 6 months of historical data and the second is forecast data for 12 months. I would like to be able to see if there is any correlation between "Group" or "Section" over a monthly period. The purpose is to see if any groups or sections could be grouped together (for a rota). So, for example, is there any correlation between RA1 and RA4_5 or RA1, Section 121 and RA3, Section31 Pivots to see total hours etc can be useful but would like to see a numerical correlation as well as a graphical. Ideally I would like to also like to be able to see average peaks and troughs over the historical and forecast period and also if possible be able to see low, core and peak periods. If I could also have historic and data overlain, that would be great.