Hi Joan,
A plugin could be written to do all that you have stated. It isn't beyond HAL to be programmed to do such things and it doesn't appear to be a difficult task to script.
I'm not sure if the appointment plugin that comes with HAL can be set to do what you want, since I have never used it. Maybe one of the forum members who uses it or has used it, can tell you if it can or can not.
Roy.