StrictDoc supports this for HTML already but not for RST.
When passed
strictdoc export ... /path/to/doctree1, /path/to/doctree2, /path/to/doctree3,
the following is generated:
output folder:
- doctree1/
- contents
- doctree2/
- contents
- doctree3/
- contents
and all three doctrees' requirements are merged into a single documentation
space with cross-linking possible.
The question is if it is worth supporting this case further or StrictDoc should
only work with one input folder with a single doc tree.
This draft requirement is the first attempt to organize this information.