[dba-SQLServer] Append only new records

I am building a table of known validated addresses in the US.  For my
purposes all I have is Address, city, state, zip and HashAddr.  HashAddr is
a has which is guaranteed to be unique given the input which is the address
fields given.  

In Access you could append records in at random and those records which did
not collide with a unique index goes in, and those that do collide do not go
in.  Obviously an index on the HashAddress will be the unique index.  Is it
possible to do the same kind of thing in SQL Server?  When I have tried this
before (in SQL Server), the whole process aborted if a collision occurred,
with no records appended if there was any collision.

John W. Colby
Colby Consulting
www.ColbyConsulting.com