Note: These options are only for dynamic objects.
If the bullet tag is on an xpEmitter, modifiers and forces are included/excluded via the emitter Modifier tab.
In this animation, there are scene modifiers, affecting the dynamic objects. Same System is enabled, so that the dynamic objects are not affected by the xpTurbulence modifier from the alternate system.
Note: The particles are being affected by an xpGravity modifier, rather than the xpBullet gravity; in order to achieve this, there are two options.
You could set xpBullet world Gravity to 0 (zero) cm in the Project Settings, X-Particles tab (as with all xpBullet objects). Alternatively, you could enable Use Local Gravity at zero cm in the tag, Forces tab, to affect the individual object. The xpGravity modifier will then be creating the gravity effect and any modifier-related mapping or use of fields can be created (otherwise a limitation of sticking to the xpBullet gravity).
If this box is checked, rigid body and soft body dynamic objects will respond to the influence of any modifiers in the scene.
If enabled, the tag will only work in conjunction with modifiers which are child objects of the same System.