Daphne and everyone,
There are a good many Beiser's that come from Rheinpfalz and yes I would say most... I do not know first hand that all Beiser's are related however it would not surprise me to find that we are.
The next bit of information all comes from my own personal research and may not apply to your direct lines
The families I have thoroughly researched (there's still a lot to do) have all had big families. There are a few exceptions of course. They are or have been for many generations - Catholic. Some of them were farmers, judeges, stone masons, blacksmiths, etc.
Some stayed in Germany while others went abroad such as to the United States, Australia, Canada, Russia, etc. There are some very famous Beiser's - authors, actors, and singers.
Here is a link of some of the Beiser's that came into the United States via Ellis Island:
http://www.ellisisland.org/search/matchMore.asp?kind=exact&a...I'll try and answer any other questions you might have.
Charity