Forcing pagination by something other than post count

So I’m definitely straying from the beaten path here, but I’d appreciate any advice.

I’m using WordPress to design a web-app type thing to display stories in a dynamic, multi-featured way. To do this, I’ve set up my main page (though this will likely change to a custom page later on) to display the content of each post (all of which are short) in a narrative, sentence/paragraph way.

See the in-progress site here: http://a-tattoo-of-myself.empyreancorpus.com/

What I need is a way to break the body of the text up into multiple pages. Since this is just the output of a query_post, it seems like normal pagination is the way to go.

The problem with this is that I’d like to avoid having that pagination occur simply on a post count (such as posts_per_page=3). I need more control than that.

The ideal solution would be to force the pagination to occur when it comes across a post with a specific tag, something like this:

if (has_tag ( 'page' )) then push the rest of the query_posts results onto the next page. Ideally, I’d put the “page” tag on everytime I wanted a new page, thus creating results pages that break exactly where I need them.

Is this even possible?

If it is, I realize it may be a huge customization task, but even if I can get an idea of how huge and where to start, I’d be grateful.

Thanks in advance.