html heading conversion (filter) and merging commands

[myfta]

I have been doing simple tasks with Pandoc for some time, but now I need to tackle something more challenging.

I have a file in RTF format.
Step 1: is to convert it to HTML
Now I want to chunk the HTML at level 1 headings, but the problem is the headings are not defined by a <h1></h1> tags but by <p><strong></strong></p>.
Step 2: Edit the HTML in a text editor replacing <strong></strong> by <h1></h1>.
Step 3: Run Pandoc with -t chunkedhtml

1. How can I eliminate the use of the manual text editing step? Using a Lua filter in Pandoc, may be? My Lua filter needs to be able to find the sequence <p><strong>...</strong></p> and replace it with <h1>...</h1>. The Lua filter guide doesn't seem to give an example of how to find a sequence of html tags or the syntax to replace them.

2. Is it possible to get all the way from the RTF file to my chunked final output by concatenating the Pandoc commands?

Thanks.