Consider the following premises. For all y, if y were a bartender, then y is playing squash. For all y, if y plays squash, then y is a scientist. There is at least one y for which y is a scientist if and only if y is a bartender. Can we infer the following from them? There is at least one y for which y is a scientist if and only if y is a bartender.
That is one of the premises. Therefore, the answer is yes.