Making skeleton files

I wish to write a long paper in sections. At any one time I want to have the text of one section up (in Abiword). But I want to be able to construct a skeleton document with markers for each section that I can replace with the full text of chosen sections, to see how they fit together. Is this possible?
  So the skeleton might look like this:
      Long Paper.
          1. A newfangled way of writing long papers.
             1.1 Section 1.1 marker
             1.2 Section 1.2 marker
, . . .
          2. Examples of its use.
              2.1 Section 2.1 marker
               . . .
- where the Section n.m are perhaps underlined in blue print (where did I see that used for replaceable references?)