You would do this via a check constraint, see here: http://www.w3schools.com/sql/sql_check.asp
Yes you can put regex in a check constraint, here is an example:
CREATE TABLE dbo.PEOPLE (
name VARCHAR(25) NOT NULL
, emailaddress VARCHAR(255) NOT NULL
, CONSTRAINT PEOPLE_ck_validemailaddress CHECK ( dbo.RegExValidate( emailaddress, N'^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$' ) = 1 )
)
Your regular expression would be: [A-Z][A-Z][A-Z][-][0-9][0-9][0-9][0-9][0-9][0-9][0-9]
Here is a great tool to build and test reg expr http://www.regexr.com/