Sorry, I have been in the Middle East as a mobilized reservist. Cramps my genealogist writings! Anyway check the Maryland 1870 Census Index there are some Jacobs and Issacs several of your names in there. I was just looking at the Maryland Index for 1870 the other day. I saw about 100 Gross families in Maryland...Adam to William. I will probably go back next week and see if I can see anything.