Grouping consecutive page numbers for index (xslt 1.0)

Hello,

Would really appreciate some guidance with the following problem.
I'm stuck with XSLT 1.0.
Any pointers as to the best approach would help.

INPUT:
<pages>
	<page>1</page>
	<page>2</page>
	<page>3</page>
	<page>6</page>
	<page>12</page>
	<page>13</page>
	<page>14</page>
	<page>15</page>
	<page>16</page>
</pages>

DESIRED OUTPUT:
<pages>
	<page>1-3</page>
	<page>6</page>
	<page>12-16</page>
</pages>

Regards.

--
Kevin