Whats the maximum amount of groups?

I've got 4 and the 4th is not showing when i type /reward

{
  "Chat Commands": {
    "Chat Command - Reward Menu": "reward",
    "Chat Command - Vote Checking": "vote"
  },
  "Messaging Options": {
    "Activate automated broadcasting": true,
    "Automated broadcast timer (minutes)": 30,
    "Message color (Primary)": "#838383",
    "Message color (Secondary)": "#838383"
  },
  "Reward List": {
    "0": {
      "Reward Cost": 1,
      "Reward Items": [
        {
          "Item Amount": 1,
          "Item Shortname": "supply.signal",
          "Item Skin ID": 0
        }
      ],
      "Reward Money (Economics)": 0,
      "Reward RP (Server Rewards)": 0
    },
    "1": {
      "Reward Cost": 6,
      "Reward Items": [
        {
          "Item Amount": 1,
          "Item Shortname": "smg.mp5",
          "Item Skin ID": 0
        },
        {
          "Item Amount": 200,
          "Item Shortname": "ammo.pistol",
          "Item Skin ID": 0
        }
      ],
      "Reward Money (Economics)": 0,
      "Reward RP (Server Rewards)": 0
    },
    "2": {
      "Reward Cost": 6,
      "Reward Items": [
        {
          "Item Amount": 1,
          "Item Shortname": "rifle.bolt",
          "Item Skin ID": 0
        },
        {
          "Item Amount": 100,
          "Item Shortname": "ammo.rifle",
          "Item Skin ID": 0
        }
      ],
      "Reward Money (Economics)": 0,
      "Reward RP (Server Rewards)": 0
    },
    "3": {
      "Reward Cost": 15,
      "Reward Items": [
        {
          "Item Amount": 1,
          "Item Shortname": "lmg.m249",
          "Item Skin ID": 0
        },
        {
          "Item Amount": 1000,
          "Item Shortname": "ammo.rifle",
          "Item Skin ID": 0
        }
      ],
      "Reward Money (Economics)": 0,
      "Reward RP (Server Rewards)": 0
    },
    "4": {
      "Reward Cost": 20,
      "Reward Items": [
        {
          "Item Amount": 1,
          "Item Shortname": "l96",
          "Item Skin ID": 0
        },
        {
          "Item Amount": 1000,
          "Item Shortname": "ammo.rifle",
          "Item Skin ID": 0
        }
      ],
      "Reward Money (Economics)": 0,
      "Reward RP (Server Rewards)": 0
	}
  },