Currently, I have assigned recordID's to rows, which are based on site address. I need to have each set of records, filtered out based on that record ID to perform additional analysis

The number of groupings, 6 as shown in the picture above, will vary every year.
Once I have the groupings separated from each other, I must then calculate the average book value for the year. The calculation should be as follows
for every row item that has a prior year date (2016) in the picture above, sum book value and that will become the Value for January.
That will then be the value for the following months, until a new row item is presented, which will then be added. (see below for example)
each grouping, based on recordID and site address will be exported into its own excel tab.
I have tried to create a batch Macro, multi formula's and a modified running total formulas to no avail.
Any help is appreciated