I'm not sure I understand what you mean by table "set"s... the way I would build this table is with a row called "priority" which would be a tinyint (you could even make it a boolean if you anticipate only having 2 levels of priority, but a number is nice so that you can say "A is more important than B, but B is more important than C").
Therefore I could write the following SQL:
SELECT * FROM News WHERE priority = 1
And another SQL statement:
SELECT * FROM News WHERE priority > 1
This will work well if your site gets relatively little traffic. For a higher volume site, keep in mind that each database call is expensive, and you would be advised to use a single SQL statement and cache the results:
SELECT * FROM News ORDER BY priority
Then for each row where priority = 1, push its contents to an array, or append it onto the end of one string; if the row has a priority > 1, push it onto another array or append it onto another string, etc.
This may or may not have been the info you were looking for. :-)
Also--
Date values returned to PHP from SQL are for all practical purposes string values, not UNIX time values. You will have to massage them accordingly to change their format (strtotime is your friend).
