[TYPO3] Inserting HTML after every third element

[Ron Hall]

Hello All,

I want to insert some HTML after every third record when rendering  
content. Basically I need to insert a clearing div. Like this:

Record 1
Record 2
Record 3
MY HTML (clearing div)
Record 4
Record 5
Record 6
MY HTML (clearing div)
Record 7
Record 8
Record 9
MY HTML (clearing div)
Record 10
Record 11
MY HTML (clearing div)

Any suggestions on how to do that? Also, the last "MY HTML" is not a  
big deal. I can insert that another way.

Thanks,
Ron Hall