start/stop checking functionality

I've been working on a module to duplicate the functionality of a Windows freeware program called Webmon. In essence, the module periodically checks the HTML source of specified pages for text in-between some start and stop point and saves that text to a node revision when it has changed. My module is working as is, but it's built using CCK fields and I'm now working on a rewrite to make it stand-alone.

I'd like to keep with the simple start/stop text method for specifying what to check, in order to make the module more approachable to novice users. I've been using a library by Michael Schrenk, that provides a return_between() function.

I'm wondering if there is a way to replace the other library using your module. I'd like to add an advanced checking option to my module eventually, using your XML/XPath functionality, but it would be nice to be able to altogether replace the other library with your module. Any ideas or thoughts?