diff --git a/control/zone.hpp b/control/zone.hpp
index bc08f48..406af13 100644
--- a/control/zone.hpp
+++ b/control/zone.hpp
@@ -89,6 +89,17 @@
         }
 
         /**
+         * @brief Sets the decrease allowed state of a group
+         *
+         * @param[in] group - A group that affects speed decreases
+         * @param[in] isAllow - Allow state according to group
+         */
+        inline void setDecreaseAllow(const Group* group, bool isAllow)
+        {
+            _decAllowed[*(group)] = isAllow;
+        }
+
+        /**
          * @brief Sets a given object's property value
          *
          * @param[in] object - Name of the object containing the property
@@ -487,6 +498,11 @@
         std::map<const Group, bool> _floorChange;
 
         /**
+         * @brief Map of groups controlling decreases allowed
+         */
+        std::map<const Group, bool> _decAllowed;
+
+        /**
          * @brief Map of group service names
          */
         std::map<const Group, std::vector<Service>> _services;