Separate Responsibilities
Let the weapon State own weapon handling and the injury State own injury posture. Prove both independently first.
Stackable Versus Exclusive
Weapon + Injury is commonly stackable. Rifle + Pistol is commonly an Exclusive Group because they are alternatives for the same semantic slot.
Inspect Overlap
Check shoulders, clavicles, spine, pelvis, and arms. Decide which State should contribute later on overlapping bones and whether Source Motion should preserve lower-stack contribution or replace it.
Stable Stack Order
Choose Stack Order based on semantic composition, not activation order. After transitions settle, requesting Weapon then Injury should produce the same fully active result as Injury then Weapon.
Use One Stack
Keep compatible Sets in one request and one normal Stack when they need shared ordering and conflict resolution.
Verify Independent Exit
Deactivate only Injury and confirm Weapon remains. Reactivate Injury, then deactivate only Weapon and confirm Injury remains.