I looked at your HAMMAN(N) web page (http://www.familytreemaker.com/users/w/a/l/Rob-A-Walker/GENE10-0001.html) to see if there is any connection with my HAMMAN(N)s.There might be if your link to the Palatinate area is to Lachen.
I did want to point out that in the section on the meaning of the HAMMAN(N) name, as quoted from "THE ECHO, MAY 1998, No. 46", there are connections made to Anglo-Irish names.This should not be!HAMMAN(N) is a German name and the coincidence that some HAMMAN(N)s upon arrival in the US changed it to HAMMOND should not lead one to then reverse the process and apply the meaning of HAMMOND back upon HAMMAN(N).It simply cannot work this way!You might want to pass this along to your family organization.They need to know that they are passing along "mythology", so to speak.The linguistic term for this process is called "folk etymology."Any references to Irish names should be dropped for accuracy's sake.
The only reason HAMMAN(N)s would have ever changed their name to HAMMOND is because that once in the USA, they would have found that the English speakers here would have been familiar with the name HAMMOND and might have called them that anyway.Since they are nearly homophones, they may have given up on the original spelling (if they could even read and write themselves!) and used what everyone else used for them anyway.Again, it is IMPOSSIBLE! to make a connection to homophonic Irish names and then apply their supposed meanings on the German name.You must start with the German meaning and go backwards from there!
If your organization ever finds out whether your group is from Lachen, I would love to share information with you.I have quite a bit on the OH, IL and KS HAMMAN(N)s.