There is a site I use to find surnames, which existed in Poland. It is one that you can search for names. It from a name study, which was done by Prof. Kazimierz Rymut, of Krakow University. He is now deceased, but his research survices. At this site: http://www.herby.com.pl/indexslo.html
, I typed in Felgen* and clicked on enter. I found three surnames beginning with Felgen. These are the results:
Nazwisko Ogólna liczba Rozmieszczenie
Felgenau 7 Ci:1, El:6
Felgenhauer 7 Gd:6, Ka:1
Felgentraeger 2 Op:2
Do you think the name could have been Felgentraeger? In looking at the abbreviations of the places listed where the people were found in Poland in 1990, they are all in the parts of Poland, which were occupied by Germans and Austrians. After WW II, those not being Polish were ordered to leave. Many who were of Polish lineage stayed.
There are microfilmed records for various religions and civil records for Suwalki and the surrounding villages outside of the city limits. Do you know the religion of your ancestors? When did they leave Poland?