If I understand what you're saying correctly, you want each contributor to the various summary reports to be able to work on a single document that contains their contributions to each of those summary reports.
Such can be achieved via bookmarks and INCLUDETEXT fields.
Each contributor would have a 'topic' document consisting of, say, five Sections - one corresponding to each summary report. Each Section would be bookmarked (e.g. Apple, Banana, Cherry, Date, Elderberry).
The Summary reports would each then be comprised of whatever boilerplate text doesn't appear in the 'topic' documents plus INCLUDETEXT fields pointing to the relevant bookmark in each of the 'topic' documents.
For more, see:
Field codes: IncludeText field - Office Support