"Orphan/Widow Paragraphs" in TOCs and Nested Lists

Obviously Framemaker has the "keep with next" and "keep with previous" options in the Paragraph formats as well as the ability to control the minimum number of lines from a paragraph that show at the beginning of end of a page (widow/orphan lines).

What I'm looking for is the same kind of functionality, except with paragraphs instead of lines.  I'm running into a lot of situations with nested lists and tables of contents where the "sub-items" will be separated from the "top-level items" when the text flows to the next page.

For example:

1) Top-Level Item

2) Top-Level Item

3) Top-Level Item

   a. Sub-Item

   b. Sub-Item

4) Top-Level Item

*PAGE ENDS HERE*

   a. Sub-Item

   b. Sub-Item

What I would like to see:

1) Top-Level Item

2) Top-Level Item

3) Top-Level Item

   a. Sub-Item

   b. Sub-Item

*PAGE ENDS HERE*

4) Top-Level Item

   a. Sub-Item

   b. Sub-Item

In most lists I can just use overrides or a different paragraph format to solve the problem.  But with TOCs, it gets rid of the overrides every time I update the TOC.

I can't just use "keep with next" in the "top-level item" paragraph format, because not every "top-level item" has "sub-items" after it.  And I can't use "keep with previous" on the "sub-item" because if there are a lot of "sub-items" I want them to be able to flow to the next page, just without leaving the associated "top-level item" behind.

Are there any solutions for this problem in Framemaker?