"Augustine Welter, my Great-Great-Great Grandfather was born in the Alsace region of France. He came to the United States in the early 1800's. He settled in Milwaukee, Wisconsin. ... I am looking for the decendents of his brothers and sisters."
This is a very old posting, but have you collected the names of Augustine Welter's siblings you refer to? If they also came to Milwaukee there are possible matches in "Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950). There was a Hermann Aug. Welter who married an Anna Maria Kleinhans in 1851; also the family of an Edward G. & Augusta (Toennes) Welter in the Milwaukee area -- about 35 occurrences of the name indexed so far.
For more information contact:
Gary Rebholz, compiler/editor
Indexing Milwaukee's German newspapers continuously since 2007... helping to access our historic immigrant cultures.