Hi
I am not from your part of the world, but I am a Drost.
As far as I know my Drost name originates from Denmark, more specificly from the island of Tåsinge (Taasinge). On this island many of the large and old farmhouses is owned or has benn owned by Drosts. The family emblem is 3 horseshoes in a row with the opening below. This emblem can still be seen on the farms.
I hope you could use this information.
Regards
Thomas Drost Clausen