Tying seemingly unrelated branches together

So, I'm working on a theory that, in the not too distant past - let's say, early 1800s to late 1700s - I can connect my father's side of the family to my mother's.

Because of the insular situation of the early English families in Nassau County, even up to the 1800s, there was a lot of intermarrying going on among the Old Guard families. That goes without saying in any community with roots and a bit of isolation. See my post on my Canada cousins. Or read James Michener's "Hawaii."

Sometimes there are unrelated branches that intertwine - unrelated to each other, that is, but with the (unbeknownst to them) same connection to you. One case on my tree is my great great grand uncle, Peter Hansen Berg, who married my first cousin 3 times removed, Harriet Dauch. Harriet's grandparents, Thomas and Barbara Dauch, are my 3rd great grandparents. Peter's parents, Peter and Sophia Berg, are also my 3rd great grandparents. Harriet and Peter weren't related to each other, but Peter's niece through his brother Theodore, Millie Berg, was also Harriet's cousin through her aunt Delia. And Millie Berg is my great-grandmother.

Confused yet?

My great-great grandmother on my father's side was Meta Ricklefs Haase. Her sister, Margaret, married a man named Oscar Hudson Cornelius, who was born in Amityville on Long Island and who, it turns out, is part of the Old Guard Long Island family, the Corneliuses (the Corneliui?) As we all know, I am connected to most of the Old Guard Long Island families by blood or by marriage, but on my mother's side. And I have somewhat close cousins (second cousins several times removed) of the same time period as Oscar, with the last name of Cornelius. Oscar's father's name was William, whose father seemed to be Carman. One of my cousins, Powell Cornelius, had a father, also named William, but a different William, whose father seemed to be Richard. I know there's a connection - there's always a connection, you sometimes just have to keep going back to find it - but I guess I haven't gone far enough back to find it yet. But that would be an interesting interfamily connection for me - cousins on my dad's city, German, new immigrant by the Raynor's standard (1840s) side related to cousins on my mother's OG LI side.