These 2 women are proving to be quite elusive. Benjamin Foss arrived as a an initial settler with his wife Sarah Getchell (Mitchell). One of their 11 children was Benjamin. Benjamin (the son) married Anna Miller in Aug 1794. ref.:LDS FHL film 0011562 book 3 page 332; book 1, pg 37. (This is also Picton Press CD 6200 pg 196 of 369).
After the 11th child Sarah passed away. Benjamin (the father) married Hannah Miller 28 Sept 1800.LDS FHL film 0011562 book 1 pg 48. (This is also Picton Press CD 6200 pg 25 of 369).
Considering the size of the town of Machias in 1800 it is almost certain that these 2 women are related. As their names are so similiar I doubt that they are sisters but, 1st cousins?
What I have stated above is all I know about these ladies plus: Anna b. abt 1772 & Hannah b. abt1776.
I am posting this message on: Washington County, Maine; Maine State; Foss; & Miller forums.