declaring constants in an xml document

[Kyle]

I have an xml document like this:\[code\]<sample xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="structure"> <film> <!-- The act1, act2 and act3 play for 27000 milli seconds each--> <sequence id="film1"> <condition time="<=27000"> PLAY </condition> <condition time=">27000"> STOP </condition> </sequence> <sequence id="film2"> <condition time="<=27000"> PLAY </condition> <condition time=">27000"> STOP </condition> </sequence> </film> </sample>\[/code\]I have this time attribute and some hard coded values. Im having around 20 tags 'films' and i do not want to hard code these numbers in all the twenty films. Please let me know if there are ways to declare some constants and use something like 'LONG', 'SHORT' instead of these numbers