They've never, ever declined such a service to me at HER when *A members are involved. I may depend, though, on how much work they'll be having at JTR when you get there and the details of your tickets, given your "complicated" routing. When you say that you have two tickets, do you mean one for JTR-ATH-CAI and a second one for CAI-IST-BKK? The way you've written it one could understand that the first one would be for JTR-ATH-CAI-IST and the second one for IST-BKK. Bear in mind that CI at JTR is not handled by A3 but by either Swissport or Goldair. Although waiting at this airport is not what I'd consider the best travel experience (unless you like visiting zoos), you increase your chances by arriving early and, possibly, by taking some of the work away from them by previous OLCI.