Another Invitation to talk over phone - PhD CS

[foreignstudent]

I have already posted about an earlier invite I got to talk over skype regarding my PhD application. Now I have got another mail from another professor B from the same university as the previous POI A to talk on whether our research interests align. Now I have a doubt on whether I should mention that I have been contacted by Prof A already or should I inform Prof A during interview that I have also been contacted by Prof B???  Is that a proper etiquette.. please do advice..

[GeoDUDE!]

I have a question for you. If both of them want you, don't you think they are going to figure it out regardless?

[foreignstudent]

Yes that is very obvious but from what I can discern this prof B has very recently joined the University (in 2015), so there could be a possibility of not knowing.. Regardless as you said they would figure it out. But I would like to know whether I should mention about that or should I just send an affirmative mail. I just want to know the proper etiquette.