"for each" function filtered by categories

[ckasimis]

Hi,

I'm trying to make a report for payslips.
Let's supose that the first item has the category "1" and the second category "2"
I use the function.

<for each="line in o.line_ids">

---Column1-----------------Column2---------Column 3--
<line.name>-------------<line.total>
<line.name>-------------<line.total>
</for>


Now i want that items from one category go to column 2 and items from another category go to column 3. The field name is "category_id"

---Column1-----------------Column2---------Column 3--
------------------------------(category 1)---(category 2)
<line.name>-------------<line.total>
<line.name>--------------------------------<line.total>
</for>

Is this possible?

Thanks in advance
Christian