It depends largely on the HOTAS. Some of them enumerate as two separate devices and most will likely require dedicated driver support. I believe the Logitech 3D Extreme Pro is supported on XIM APEX. For other HOTAS sticks, pairing a XIM APEX with a Titan Two is the most likely solution to work.
There are Titan Two configs for popular sticks like T.Flight, X52 and Warthog. A quick search in Gtuner IV showed a number of configs for the Thrustmaster T.Flight HOTAS One and One X.
Long story short, Titan Two supports both XIM APEX and Thrustmaster HOTAS devices for XB1. How it would work is XIM APEX, mouse, keyboard & controller in INPUT-A. HOTAS in INPUT-B. Titan Two combines the input into a single output device.