Yes there is. In each Device is a Device Action List. Take the actions you would normally have in the Device Action List and put them on a button on a hidden page within each device.

Device1 - Hidden Page1 - DeviceActions (This device is coded for RF1)

Device2 - Hidden Page1 - DeviceActions (This device is coded for RF2)

Now, in the ActionList of Device1, put a Link to the "Device1 - Hidden Page1 - DeviceActions" button followed by a Link to the "Device2 - Hidden Page1 - DeviceActions).

If you are on the 'Devices' system page, now, when you press the button for "Device1", you should see actions from both Buttons executed.

Following this pattern and Links, you can mix and match Links from whatever equipment you have attached to whatever extender you might have. The Extender applied to an IR code is solely controlled by the Device in which the IR code is contained. If you 'Link' buttons, you can create action lists that execute commands using multiple extenders. Note that you may have to insert some delays from time to time but overall, this approach works.