OE in different time zones

Hey all! I've recently picked up J2 and it's going well. I'm in EST and they mostly all work in PST. J1 is all over the country so my time zone has never been too big an issue. What I'm running into in J2 are others contacting me or scheduling meetings with me at all hours of the day. I'm a consultant so technically, I set my own schedule, my supervisor and hers are all fine and respect my schedule. My question is how do I politely remind others that I'm not in their time zone and can't be available their hours with out sounding like I'm not willing to participate? Thanks all!