Loop with Excel functions possible?

Hi everyone, I am reposting this thread under another (hopefully acceptable) title. I am working on a spreadsheet regarding real estate investments and I am having trouble creating a formula that will track payments. I have the months running horizontally and I want to be able to list the houses (just numbered like 1, 2, 3, etc.) that make mortgage payments each month. Mortgage payments are made from x # of months (set to 1 now) after the house is sold until the note is sold (y # of months after the house is sold, set to 5 now). The problem I have is that say the company buys 1 or 2 houses a month and sells them a month later, after a while, they will be receiving 10 payments a month, some new ones start paying and old ones drop out. Is there an Excel formula that will give me a list of the houses making payments each month (for example, "2,3,4")? Or is this only possible through a loop in VBA? I do not know VBA so I am hoping there is a way with array formulas or something. I've attached a sample spreadsheet to make my question more clear. As you can see, I've entered the payments manually, but if I change the assumptions, I want the payment line to change automatically. Thanks for your help!sample CF.xlsx