Okay, need some XSLT help

I am working with an XML document that has DETAIL sections as such:

Code:

---

- <DETAIL>
  <ITEM_NUMBER>004154BKWH 3XL</ITEM_NUMBER>
  <DETAIL_7>24.00000</DETAIL_7>
  <DETAIL_8>EA</DETAIL_8>
  <DETAIL_9>11.95000</DETAIL_9>
  <SALESTAX>0.00000</SALESTAX>
  <LINE_NUMBER>840</LINE_NUMBER>
  <GTIN>08402350933274</GTIN>
  <style>4154</style>
  <color>BKWH</color>
  <sizecode>3XL</sizecode>
  <description>LONG SLEEVE HOOK TEE</description>
  </DETAIL>

---

The problem I am having with my XSLT file is that in the spec I am working with I separate out charges (anything where the STYLE begins with ZZ) from the non-ZZ items.

That doesn't pose a problem, as most of what I need I can do using the choose-when-otherwise construct.

The problem is that each type (ZZ versus non-ZZ) has to have its own sequential counter. I am stumped on how to do this and searching through documentation on the recursive template proves to be nothing more than "this does this."

Can someone help me?