Different expiry notifications per package

Hi,

I’d like to have different listing expiration emails for different packages. So, for example, the expiration notification message to a customer who has a free listing may include something about incentive (i.e. a discount coupon) to upgrade, whereas I would not want to necessarily offer the same to existing paying customers. Likewise I don’t think the expiration message for places and other CPTs should be the same as the message for events.

So, is there any way we can set up different expiry notifications per package ID? I’m guessing there may be a way to do it with hooks, but I wouldn’t have a clue where to start with this.

Your advice is very much appreciated.

Thanks,
Mark