recursive template call, howto

<group>
 <line id = "1"/>
</group>
<group>
 <line id="2"/>
</group>
<group type="complex">
 <line id="3"/>
 <line id="4"/>
 <line id="5"/>
 <line id="6"/>
</group>
<group>
 <line id="7"/>
</group>
<group>
 <line id="8"/>
</group>

The idea behind the data is that there are two types of groups: simple
and complex.  The simple do not have a "type" attribute (it could if it
would help things).  The end result should be HTML where the first two
simple groups are in one HTML table, than there is a second table for
each of the complex groups and thing a final table for the last three
simple groups.  The order of simple and complex groups is random.

My thought was when the first simple group was encountered, call a
recursive template starting at the simple group and building a nodeset
of lines until a complex group or the end was encountered.  I cannot
figure out how to do that in xsl.  Am I on the right path? If so, how
do I do it?  If not, what is the right path?