Using multiple (different) rulesets in one plugin

Is there any way to use multiple different rulesets in a single Plugin?

Example 1:
I want to write an advanced filesystem check. I’d like to use the parameters from standard checkmk filesystem rulesets but want to add a second ruleset containing some special settings. Copying the original ruleset would be possible but doesn’t seem like the correct way to achieve this efficiently.
Example 2:
I have a plugin with fairly complex configuration options. For better readability, I’d like to organize these rules in different groups or rulesets.

Is there any way to achieve this or maybe a smart alternative procedure to handle cases like this?