Not only did members of Luther's founding families intermarry, but many had connections back in their former homelands. The Luther Area Study, naturally the most extensive, has now expanded to include quite a few families of the surrounding eight townships. And it has spawned many smaller studies. Obion Co. TN is up, with more to follow, and no end in sight. In addition to the typical collection of blended families and double cousins, there are honorary titles and shirttale kin.
Titles mean no more and no less than the speaker intends.
I've found there is usually a kernel of truth in it. Perhaps the two lines are related by marriage. Perhaps they came to Luther from the same small town and the link is found in previous generations who lived there.