diff --git a/common/ruletypes.h b/common/ruletypes.h
index c0e740493..82c4f9ecc 100644
--- a/common/ruletypes.h
+++ b/common/ruletypes.h
@@ -378,6 +378,7 @@ RULE_BOOL(Spells, CazicTouchTargetsPetOwner, true, "If True, causes Cazic Touch
 RULE_BOOL(Spells, PreventFactionWarOnCharmBreak, false, "Enable spell interupts and dot removal on charm break to prevent faction wars.")
 RULE_BOOL(Spells, AllowDoubleInvis, false, "Allows you to cast invisibility spells on a player that is already invisible")
 RULE_BOOL(Spells, AllowSpellMemorizeFromItem, false, "Allows players to memorize spells by right-clicking spell scrolls")
+RULE_BOOL(Spells, InvisRequiresGroup, false, "Invis requires the the target to be in group.")
 RULE_CATEGORY_END()
 
 RULE_CATEGORY(Combat)
diff --git a/common/spdat.cpp b/common/spdat.cpp
index d7b38096e..e5d85ba9e 100644
--- a/common/spdat.cpp
+++ b/common/spdat.cpp
@@ -260,6 +260,18 @@ bool IsDetrimentalSpell(uint16 spell_id)
 	return !IsBeneficialSpell(spell_id);
 }
 
+bool IsInvisSpell(uint16 spell_id)
+{
+	if (IsEffectInSpell(spell_id, SE_Invisibility) ||
+		IsEffectInSpell(spell_id, SE_Invisibility2) ||
+		IsEffectInSpell(spell_id, SE_InvisVsUndead) ||
+		IsEffectInSpell(spell_id, SE_InvisVsUndead2) ||
+		IsEffectInSpell(spell_id, SE_InvisVsAnimals)) {
+		return true;
+	}
+	return false;
+}
+
 bool IsInvulnerabilitySpell(uint16 spell_id)
 {
 	return IsEffectInSpell(spell_id, SE_DivineAura);
diff --git a/common/spdat.h b/common/spdat.h
index e4ffb23be..3bcb17487 100644
--- a/common/spdat.h
+++ b/common/spdat.h
@@ -1083,6 +1083,7 @@ bool IsPercentalHealSpell(uint16 spell_id);
 bool IsGroupOnlySpell(uint16 spell_id);
 bool IsBeneficialSpell(uint16 spell_id);
 bool IsDetrimentalSpell(uint16 spell_id);
+bool IsInvisSpell(uint16 spell_id);
 bool IsInvulnerabilitySpell(uint16 spell_id);
 bool IsCHDurationSpell(uint16 spell_id);
 bool IsPoisonCounterSpell(uint16 spell_id);
diff --git a/zone/spells.cpp b/zone/spells.cpp
index a26c9e2dc..12bc97493 100644
--- a/zone/spells.cpp
+++ b/zone/spells.cpp
@@ -431,6 +431,28 @@ bool Mob::DoCastSpell(uint16 spell_id, uint16 target_id, CastingSlot slot,
 	// ok now we know the target
 	casting_spell_targetid = target_id;
 
+	if (RuleB(Spells, InvisRequiresGroup) && IsInvisSpell(spell_id)) {
+		if (GetTarget() && GetTarget()->IsClient()) {
+			Client *spell_target = entity_list.GetClientByID(target_id);
+			if (spell_target && spell_target->GetID() != GetID()) {
+				if (!spell_target->IsGrouped()) {
+					InterruptSpell(spell_id);
+					Message(Chat::Red, "You cannot invis someone who is not in your group.");
+					return false;
+				}
+				else if (spell_target->IsGrouped()) {
+					Group *target_group = spell_target->GetGroup();
+					Group *my_group     = GetGroup();
+					if (target_group && my_group && (target_group->GetID() != my_group->GetID())) {
+						InterruptSpell(spell_id);
+						Message(Chat::Red, "You cannot invis someone who is not in your group.");
+						return false;
+					}
+				}
+			}
+		}
+	}
+
 	// We don't get actual mana cost here, that's done when we consume the mana
 	if (mana_cost == -1)
 		mana_cost = spell.mana;
@@ -2786,6 +2808,7 @@ int Mob::CalcBuffDuration(Mob *caster, Mob *target, uint16 spell_id, int32 caste
 	    spell_id != 287 && spell_id != 601 && IsEffectInSpell(spell_id, SE_Illusion))
 		res = 10000; // ~16h override
 
+
 	res = mod_buff_duration(res, caster, target, spell_id);
 
 	LogSpells("Spell [{}]: Casting level [{}], formula [{}], base_duration [{}]: result [{}]",