Not sure about the EyeX, but the Gaze SDK and the REX trackers we use certainly can.
Since it allows you to control the trackers directly, there is some features that is (currently) exclusive to Gaze SDK.
But use the EyeX Engine if possible.
Our application is highly specialized with many hardware, software and UI requirements, so the EyeX Engine is insufficient because of that.
Not many regular users is going to buy multiple EyeX trackers, and your app will be unusable as soon as they are built into laptops and tablets (We have a controlled environment so it is no problem for us).