SQL & PL/SQL

Hi,

I'm creating a trigger. In the trigger, I would like to get all inserted (or updated) rows in order to do a "group by" statement and traverse only a subset of all inserted rows. How would I go about doing that? In SQL Server, there is the inserted or deleted virtual tables which hold all the inserted/deleted rows in a session. Is there anything equivalent in Oracle? The Old and New variables are not quite it, since they only reference one single row at a time.

Thanks