list Touchers;

default
{
    touch_start(integer n)
    {
        if (llDetectedKey(0) == llGetOwner())
        {
            integer length = llGetListLength(Touchers);
            integer index;
            // Loop through every index in the list and display the element
            for (index = 0; index < length; ++index)
                 llOwnerSay(llList2String(Touchers, index));
        }
        else
        {
            // Check if this name is already present in the list
            if (llListFindList(Touchers, (list)llDetectedName(0)) == -1)
                // Not present, add it.
                Touchers += llDetectedName(0);
        }
    }
}