how to update a variable (grouping question)

I am trying to retrieve data from a table structure (xml table) where
after every few rows a special row appears which contains a piece of
data which is relevant to rows appearing immidiatley after it (i.e.
its next few siblings).  I am having hard time figuring out how to
achieve this without a dynamically assigned variable in XSL.

Test data looks like this:

<schedule>
	<row type="header">
		<col>January</col>
		<col>Opponent</col>
	</row>
	<row type="data">
		<col>10 at 6pm</col>
		<col>Dallas</col>
	</row>
	<row type="data">
		<col>21 at 8pm</col>
		<col>New York</col>
	</row>
	<row type="data">
		<col>31 at 8pm</col>
		<col>Chicago</col>
	</row>
	<row type="header">
		<col>March</col>
		<col>Opponent</col>
	</row>
	<row type="data">
		<col>16 at 9pm</col>
		<col>Houston</col>
	</row>
	<row type="data">
		<col>31 at 7pm</col>
		<col>Sacramento</col>
	</row>
</schedule>

and the desired output is:
<schedule>
	<date>January 10 at 6pm</date>
	<date>January 21 at 8pm</date>
	<date>January 31 at 8pm</date>
	<date>March   16 at 9pm</date>
	<date>March   31 at 7pm</date>
</schedule>

basically what I am trying to figure out is how I can save the value
of col[1] in a varaible WHEN row[@type='header'] and then append the
value of this variable to all of the following col[1] values UNTIL the
next row[@type='header] is reached ?

Any suggestions, pointers, hints  ?

-sm