Questioning on other witness's testimony

The general rule is that you may not "pit" one witness against another. So questions like "are you surprised that XY said ABC" are generally improper. Such questions are irrelevant and, at best, call for an opinion on credibility.

All that said, questions about issues put to other witnesses are proper. Indeed, it is correct to ask a witness precisely the same questions asked of an earlier witness. The trier of fact can then compare the answers and decide which witness is to be believed.