Been watching/reading your Hauch family stories with interest.
First off, I am not related but have been in and out of the 'Germans from Russia' sites for many years.
This may be of interest to you: http://www.ahsgr.org/
A bit of history. Catherine the Great was German royalty that married into the Tzar's of Russia. She was from Westpruessen (West Prussia) originally. She was the instigator of bringing German farmers to the Ukraine (including Volhynia) for the reason they (Germans) knew more about farming than the locals. The Germans were given automomy (in regards to government, religion, laws) of everything they had in Germany.
Then, the Russian Revolution and most likely some jelousy of the locals and they were forced out, either to Germany, America, Canada, Brazil or Australia.
So... didn't matter if you were born in Russia (Ukraine), if you had German blood, you were gone and so was your land and businesses.
I will let you get back to your Hauch business!
Regards, Robert Lipprandt