plugin group message for lucky chair

key group;
string url = "secondlife:///app/group/";
default
{
    state_entry()
    {
        list dets = llGetObjectDetails(llGetKey(),[OBJECT_GROUP]);
        group = llList2Key(dets,0);
    }
    changed(integer change)
    {
        if(change & CHANGED_LINK)
        {
            key av = llAvatarOnSitTarget();
            if(av)
            {
                if(!llSameGroup(av))
                {
                    llSleep(0.5);//to give the chair time to send it's default message first
                    llRegionSayTo(av,0,"Please join " + url + (string)group + "/about to use this chair");
                }
            }
        }
    }
}