some Advice about Group of Grid

while using databinding in group grid, there's a problem.
group is a child component of rows,brother of row:

<grid>
<rows>
<group/>
<row/>
<row/>
</rows>
</grid>

but in the data structure, usaually we hold group_date as the parent of row, the child of rows.
without databinding ,we can create group component dynamiclly, but while using databinding,there's a problem.

here's an example:
this is what i want, but it's wrong for current zkbin,because i recognize group component as the parent of row.

---

<grid model="@{controller.country}">
<rows self="@{each='provence'}">
<group self="@{each='provence.city'" label="@{provence.name}">
<row><label value="@{city.name}"/><label value="@{city.people_number}"/><label value="@{city.car_number}"/>
</row>
</group>
</rows>
</grid>

---

here is what i want to say, the group component should be the parent of row.