Click on the grey area of the Audio Track, where the name is (e.g. Audio 1), and look in the lower left of the Deck at the bottom. You should see a coloured bar with ‘Out’ written underneath. Right-click it, and select Surround. (You may need to go into Edit > Preferences > Format and select ‘5.1 Surround’ to get this, not sure.)
Once you’ve got Surround selected, you’ll see a circle with speaker icons. Right-click on the dot in the centre of the circle (which represents the player position) and select Automation > Surround Direction or Automation > Surround Extent.
If you add a parameter - the preset Direction one seems the most applicable - then you can map the surround direction and extent to the parameter, and link the parameter to your game engine. You’ll need to define a Surround Extent of less than 360 degrees to direct sound to specific degree locales.
These might help:
I’ve not tested this, but it should work
As an additional tip (that may be related to your question), you can isolate sounds completely by clicking on the speaker icons that sit outside the Surround circle in the lower left. When you click them, the speakers will go dark grey, and you will mute that speaker’s output. Might be handy if you want 4-way surround on a 5.1 system, for example.