Prevent recalling enemy units.

OpenRA.Mods.CA/Traits/SupportPowers/RecallPower.cs

@@ -47,6 +47,9 @@ sealed class RecallPowerInfo : SupportPowerInfo
 		[Desc("Target types that cannot be recalled.")]
 		public readonly BitSet<TargetableType> InvalidTargetTypes = default(BitSet<TargetableType>);
 
+		[Desc("Player relationships that can be recalled.")]
+		public readonly PlayerRelationship ValidRelationships = PlayerRelationship.Ally;
+
 		[CursorReference]
 		[Desc("Cursor to display when the targeted area is blocked.")]
 		public readonly string TargetBlockedCursor = "move-blocked";
@@ -178,6 +181,9 @@ public bool IsValidTarget(Actor a)
 			if (a == null || !a.IsInWorld || a.IsDead)
 				return false;
 
+			if (!info.ValidRelationships.HasRelationship(Self.Owner.RelationshipWith(a.Owner)))
+				return false;
+
 			var targetTypes = a.GetEnabledTargetTypes();
 
 			if (!targetTypes.Overlaps(info.ValidTargetTypes))