Carla,
your message sounds rather interesting. I am searching for the DOMMER family from Westprussia and have determined connections of American families to my ancestry. They immigrated through Canada to the US, but not to PA. Therefore I do assume that your family is from another line: in southern Germany there is also a big "clan", which can be traced back till 1618.
Do you know from which area or town in Germany your ancestors would have come ?
Looking forward to hearing from you,
Eberhardt Dommer