Well how about that: I figured out how to answer my own question. In case
you're interested, here's how I did it.
The key is to realize that I can find the text surrounded by a known set of
tags using a grep search, with the option "selecting match" turned on, and with
the "starting at top" opt
I have a BBEdit document looking something like this:
{Tag_A}
Some text, could be multiple sentences, multiple paragraphs.
{/Tag_A}
Some other text here
{Tag_B}
More text here. Could be multiple sentences, multiple paragraphs, as above.
{/Tag_B}
{Tag_A}
Some text, could be multiple sentences, m