There are several ways to accomplish what you are trying to do.  Triggers are one option.  Another option is to set up the tables as described in BOL.  Do a search on "Cascading Referential Integrity Constraints".  The quick version is that when you create the father and child tables you can set up the foreign key reference constraints to cascade when a row is deleted in the parent table.  I have heard debates pro and con whether this is a good strategy to use.