MS Word - Need way to name blocks of text

I need something in MS Word that can be hidden that will identify specific paragraphs or blocks of text.

I'll be embedding these markers in a large MS Word document.

Something like:

Line one
<<Line Two Begins here>>
Line two
<<Line Two Ends here>>
Line three

In the above example Line Two is surrounded by <<  >> markers.

I will then use C# code to find these markers to show only the text between them.

I looked at Fields but they are too much trouble.

Bookmarks do not help because you cannot easily see their names.

And I do not see how section breaks could help.

Is there something in MS Word like C# comments:

 /* comment here */

that can be hidden?

Thanks