I don't know how feasible it is to arrange when you get there and suspect it's something you need to sort out well in advance. However, some of the tour groups are led/accompanied by survivors.

From personal experience, it makes a huge difference to tour the two camps (Auschwitz and Birkenau) with such a survivor. You can only imagine the difference it makes to your visit to be listening to a survivor stand by the railway lines in Birkenau and describe "when we were forced off the trains" and "we stood in line" and "my mother was told to go in a separate line" and "I never saw her again"......

Well worth doing if you can.