Thank you for the question on the Patriarch Jacob becoming the father of the Israelites and Samaritans.
Jacob is not the father of the Samaritans. The Assyrians conquered the Northern Kingdom in 732 BCE. They imported people into the land and those individuals married the Israelites. Thus they became to be called Samaritans.
It is also possible through Esau’s marriage of different people group that he may have contributed to the intermarriage of non-Jews to Jacob’s descendants.
SUMMARY: Jacob did not father the Samaritans.
For further insight and discussion: