Option for XML to stop at a certain end tag

Currently a page stops in the middle of nowhere.
It would be nice if you can say for XML files that it has to stop at a certain end tag.

How I see it for me is that when it reached the amount of characters in the config file it will look before and after that amount of characters to said end tag. When deciding where to stop a page you can compare those 2 and see which one is the least amount of characters away from the config max character count.