Answer:
US OFAC sanctions are totally separate from the UN Sanctions list, although there is crossover. Lists other than OFAC are purely a risk management decision (and yes, I know OFAC is a risk decision as well, but there is an actual US law prohibiting US companies and citizens from doing business with anyone on the OFAC lists).
Your vendor may combine all into one search and the bank must discern which list has been hit by reviewing carefully.
First published on BankersOnline.com 10/24/11