I.e. you have a single shape representing the coastline of your map, and a single path representing all the borders inside it, can you use that path to divide the map into territories?
EDIT: I found an extension to inkscape that does it https://inkscape.org/en/~Moini/%E2%98%85multi-bool-extension-cut-difference-division
(use multi-division tool)
Edited 2/8/2017 16:55:12