Yes, the general consensus is that not only the Sequatchie Valley branch (which are mine, and who are a branch of the VA->KY->TN group) but probably all of them are related in ways we have not fully established, and are Manx. We have a lot of info on Manx origins coming from Rawleigh Condra of California, who has visited the Isle of Man and corresponded with Condras there, and also has information on the Irish sites named for Condras. Condra (and its variants) is, as you know, an indigenous Manx name, Celtic in origin. Unfortunately, Rawleigh is not on line at present, so I can't put you in touch with her. The earliest Condras recorded in this country date to about 1640, and appear to have begun migrating from Man after the English repressions of 1643 under Lord Stanley. It's not a very common name, so is does not seem improbable that everyone who has it is related to everyone else who does. But the common roots are surely so far back in history we will never connect everyone with documents.