How do I put a date column from a collection as a header for a XHTML Table?

Hi,

what’s the best way to achieve this. Say I have a data collection
ordered by a date column (ASC or DESC) like this one.

Date;Name;Amount

20071001;John;500
20071001;Jim;400
20070902;Bob;300
20070901;Ron;700

Now, I want to output an XHTML Table which groups the records by date,
effectively rendering a table row with only the date as a headline:

Name - Amount

October 01, 2007

John - 500
Jim - 400

September 02, 2007

Bob - 300

September 01, 2007

Ron - 700

…etc.

As this snippet will repeat itself, I would like to come up with a
helper which I send the collection to, and the date column to make
headers from, and get the above output back.

Some hints in the right direction would be highly appreciated.

Thanks a lot,
Manuel