>I thought I had it ready to go with my support about group index. However, based on an example the client sent me, I just want that in one of them, there is an INCLUDE clause in the middle of a CREATE INDEX command. What does that stand for?

Check this interesting article explaining the usage of INCLUDE clause

http://www.databasejournal.com/features/mssql/article.php/3787021/Exploring-SQL-Servers-Index-INCLUDEs.htm

Recommendations from this article:

Recommendations
•Indexes with INCLUDEs are a big win for frequently-called range queries.
•If access is always per-record on the clustered index, don’t add indexes with INCUDEs.
•For frequently called relatively-static data, consider using multiple indexes with INCLUDEs to cover different queries even if the KeyColumns are the same.
•Where you have created covering indexes where all the columns are in the KeyColumns, consider changing these indexes to have the minimal set of KeyColumns and the other columns in the IncludedColumns. This will lower the space requirements and speed the retrieval of records.