Hi there @jereed,
I believe you will need to regroup and select, as shown below:
dtMyDataTable = dtMyDataTable.AsEnumerable.GroupBy(Function(x) x.item("SomeColumnName")).Select(Function(i) i.First).GroupBy(Function(x) x.item("SomeOtherColumnName")).Select(Function(i) i.First).CopyToDataTable
This appears to work, though there may be a more aesthetically pleasing method
Thanks,
Josh