ButtonGroups.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class Button_Groups : MonoBehaviour {

    List<Rect> lstButtonItems = new List<Rect>();
    List<Rect> lstButtonSkills = new List<Rect>();


    void Start () {

        var width = Screen.width;
        var height = Screen.height;

        lstButtonSkills.Add(new Rect(width / 2 + 50, height / 2 + 333, 55, 55));
        lstButtonSkills.Add(new Rect(width / 2 + 105, height / 2 + 333, 55, 55));
        lstButtonSkills.Add(new Rect(width / 2 + 160, height / 2 + 333, 55, 55));
        lstButtonItems.Add(new Rect(width / 2 - 160, height / 2 + 333, 55, 55));
        lstButtonItems.Add(new Rect(width / 2 - 105, height / 2 + 333, 55, 55));
        lstButtonItems.Add(new Rect(width / 2 - 50, height / 2 + 333, 55, 55));

    }
	
    void OnGUI() {

        GUI.Button(lstButtonSkills[0], "Skill A");
        GUI.Button(lstButtonSkills[1], "Skill B");
        GUI.Button(lstButtonSkills[2], "Skill C");
        GUI.Button(lstButtonItems[0], "Item A");
        GUI.Button(lstButtonItems[1], "Item B");
        GUI.Button(lstButtonItems[2], "Item C");
    }

}