regex pattern for a reference point [on hold]

Using regex in python, I want to find a regex pattern and make the pattern a reference point for the text that follows. Then when the pattern is found again, it begins another record with the second-found-pattern as a reference point for everything that follows until the next pattern and its records.

I have been studying search, findall, and match, and group(), but I can't seem to find out how to do this. I know this isn't a perfect question, but I'm a noob. Thanks for any direction.

Here is an example of desired output:

<document>
Pattern stuff stuff stuff 
      Stuff thing 
Stuff 

Stuff stuff stuff stuff thing 

Pattern stuff stuff stuff stuff stuff stuff 
Pattern stuff stuff thing  stuff 

Pattern stuf thing 

<\document>

Desired output:

Pattern[0] stuff ...
Pattern[1] stuff ...
Pattern[2] stuff...

Another desired output:

Pattern[0] thing ...
Pattern[1] thing ...
Pattern[2] thing...