Aggregate Total Acreage And Group By For Mail Merge

I was helped on an earlier question to complete my mail merge with the following code:
selectYourTable.*
fromYourTable
inner join --DistinctNames
(selectMax(PrimaryKey) as PrimaryKey
fromYourTable
group by FirstName,
LastName) DistinctNames
on YourTable.PrimaryKey = DistinctNames.PrimaryKey
Basically this code queries my mailing list and ensures that i do not send mutiple letters to one person at the same address who might be in the batabase more than once. However, the reason they are in there more than once is that they might own additional properties. Anyway, I have a column that includes their acreage for each property in each record and I would like to add those up for each person during my query. Thought anyone? Thanks!