* @return An <code>EventPanel</code> key, or null if none appropriate.
     */
    private String getContactKey(ServerPlayer other) {
        String key = "EventPanel.MEETING_" + other.getNationNameKey();
        if (!Messages.containsKey(key)) {
            if (other.isEuropean()) {
                key = (hasContactedEuropeans()) ? null
                    : "EventPanel.MEETING_EUROPEANS";
            } else {
                key = (hasContactedIndians()) ? null
                    : "EventPanel.MEETING_NATIVES";
            }
        }
        return key;
    }