Concatenate cells based on criteria/threshold

Hello,

I am hoping to get some assistance. I have attached a variance tool which consists of two sets of data. First, the file loops through over 120 different variance files and stacks the data onto the variance comments tab using VBA (I removed a large amount of it for file size purposes). The RET Recoveries tab is the second source of data which is a hyperion pull that grabs financial data from our accounting system. In columns AC and AD of the RET Recoveries tab is a field for variance comments. I am looking to concatenate the variance comments from the variance comments tab (Column D) in column AC of the RET Recoveries tab for each time it finds revenue comments (PCRETRev) for a particular business unit (Column CN on Variance Comment tab and Column A on RET Recoveries tab) and comments in column AD for expense comments (RETax). The trick is the variance comments has 12 months of data and the RET Recovery tab has one month of data (August). I want it to concatenate comments only when amounts in column AZ -August Variance column are not equal to blank or zero and dynamic enough so when I change the month in cell E9 of the RET Recoveries tab it knows to change the column to do the criteria search on (ex: Column AZ). Hopefully this makes sense.

Thanks in Advance!