I am writing an `INSTEAD OF INSERT` trigger which validates data before insertion.

To simplify my problem: consider this as my insertion:

```
INSERT INTO Event 
VALUES ('A', 'building1', 'adress1'),
       ('B', 'building2', 'adress2'),
       ('C', 'building1', 'adress3')

```

I need to catch case in which INSERTED table contains same building with different addresses - which is not possible.

Some `IF` statement snippet would really help me here.