integer gIntScanTime = 5;
list gLstAvatarsInRegion;
list gLstAvatarsAlreadyHere;

default
{
    on_rez(integer p)
    {
        llResetScript();
    }
    
    changed(integer c)
    { 
        if (c & CHANGED_INVENTORY|CHANGED_OWNER|CHANGED_REGION)
        {
            llResetScript();
        }
    }
    
    state_entry()
    {
        llPreloadSound("GreeterSound");
        llSetTimerEvent(gIntScanTime);
    }
    
    timer()
    {
        list gLstAvatarsInRegion;
        gLstAvatarsInRegion = llGetAgentList(AGENT_LIST_REGION, []);
        integer intNumOfAvatars;
        intNumOfAvatars = llGetListLength(gLstAvatarsInRegion);   
        integer index;
        for (index =0;index < intNumOfAvatars; index++)
        {
            key id; id = llList2Key(gLstAvatarsInRegion, index);
            if (llListFindList(gLstAvatarsAlreadyHere,id) == -1)
            {
                string strName; strName = llKey2Name(id);
                string strRegion; strRegion = llGetRegionName();
                llOwnerSay(strName + " entered  " + strRegion +  " Region.\n");
                llRegionSayTo(id,0,"Welcome to " + strRegion);
                gLstAvatarsAlreadyHere = gLstAvatarsAlreadyHere + [id];
                llPlaySound("GreeterSound",1.0);
                ++index;
            }
        }
        intNumOfAvatars = llGetListLength(gLstAvatarsAlreadyHere);   
        for (index=0;index < intNumOfAvatars;index++)
        {
            list lstThisAgent;
            lstThisAgent = llList2List(gLstAvatarsAlreadyHere,index,index);
            key kyThisAgent;
            kyThisAgent = llList2Key(lstThisAgent,0);
            if (llGetAgentSize(kyThisAgent) == ZERO_VECTOR)   
            {
                gLstAvatarsAlreadyHere = llDeleteSubList(gLstAvatarsAlreadyHere,index,index);
            }
            ++index;
        }
    }
}