I'd just let it pass over you like water off a duck's back.
In my time I've met clients who tell me that they've met XYZ as if I'm going to care, I've met quite a few escorts around here - I don't socialise with any of them, I would know them to see them because I have met them but I do keep myself to myself.
There are some clients that may be innocent and believe that we all know each other, and its more a friendly 'oh I saw so and so' in the same way that you would say I saw Susan at the park, but I've also known clients who would happily get involved in this backbiting drama where they would set women off against each other. And that's not my environment. My attitude is that every single person who is in this industry is ultimately trying to keep a roof over their head and pay bills at the end of the day, just like I am, and I'm not going to get involved in any kind of nastiness. They can say what they want, but if they think I'm going to be a carrier pigeon, I sadly don't have feathers.