Can you give us some information about when and where they lived? You won't, most likely have to do what we call a merge here on Wikitree. You will just have to attach the parts of the tree you want to add here to the existing tree here and then add any additional sources, etc. to the existing profiles. You can convert the other tree to a GEDcom and them upload it here, though you do have to look at all the profiles in the new tree and skip them if the same person is already here on WikiTree. Most of us, after trying this vow never to do it again. But that's just a warning, not a prescription. If perchance your Greens lived in Licking County, Ohio, I have a lot of relatives, though not ancestors, who married Greens there. Good luck here and have fun.