[Zope] tal loop to render table

I would like to build a tal loop that renders a list of elements (widgets in my case) in a table. (for example I have a list of 9 items, then it renders a table: five rows with 2,2,2,2,1 items) the table has 2 columns, so i would need to open and close the table row every second item. I tried to check with a condition if the row is odd or even, but unopened and unclosed tags are not valid. Is there any possibiliy to do this with tal? Dennis