If I understand correctly you have two switches controlling the hallway light, the primary switch is connected to the load ( hallway light), and both hallway switches are cross linked so that either switch will turn On or Off the hallway light.
You trigger a macro that turns off the secondary switch, the one that does not have the load connected, with the expectation that because the primary and secondary switches are cross linked that would turn off the hallway light.
Hope I got that right. If not post back the actual situation.
Sending a command from EZSrve to turn off the secondary switch does not cause the primary switch (the one controlling the load) to turn off. Insteon hardware does not work that way. The device cross linking applies only to pressing the On/Off paddle of either switch, not commands sent from the outside. If you want the primary and secondary switches to turn off from an EZSrve command, you must create a Scene where EZSrve is the Controller, and each of the hallway switches are responders. The macro sends an OFF to the Scene rather than an individual switch.