Formula to count last 18 instances of occurrence (from a specific date) to perform a SUMIF

Hi,

I have historical football results from the last 15 years as per attachment. What I would like to do is take a specific row and have a formula that looks back at only the last 19 home games for a team so I can calculate how many goals have been scored in that game.

On attached, column A has date, C has the home team, D has the away team and I has the total goals scored in the game. So for example on row 4443 there is the fixture Liverpool vs. Arsenal so in column Y I'd like to be able to have a formula that looks back at only the last 19 home games that Liverpool have played before the date of this match (as per column A - 03/03/2012) and then adds up how many goals (column I) have been scored in those 19 games.

In column Z I'd also then like to be able to look at a similar thing but the last 19 away games that Liverpool (the home team in this match) have played before 03/03/2012 and do the same formula for total goals in those last 19 when Liverpool playing away. I would then copy these fomulas all the way down from row 3 to the end of the data so I have a continual rolling record for each upcoming game.

I am not too bad with excel and understand a large range of the formulas and logic but I'm afraid this is beyond me and would massively appreciate any help.

Thanks!