Believe what you may be looking for is the MERGE statement. For a discussion and example of how it works:
http://www.simple-talk.com/sql/learn-sql-server/the-merge-statement-in-sql-server-2008/
If you would/could post the table definition, some sample data and desired result someone may be able to assist you with tested sample T-SQL.
To provide the sample as I suggested please click on the first link in my signature block and read the article. The article has sample T-SQL to allow you to post the table definition, some sample data and desired result simply and easily.