Hello Dan,
Excellent question you have there, thanks for reaching out!
If that is for one event, then you can easily use the Global Stock feature.
When creating an event, in the ticket section tick the checkbox “Enable global stock”, then save the event. If you start adding tickets before saving this setting, then you will not be able to use it for tickets.
After the new settings is saved add a new ticket or edit an existing one.
You now should see a dropdown titled “Global stock mode”. There select “Use global stock”. Create all 3 tickets the same way.
You are done. 🙂
Here’s a screenshot of the settings.

Now people can buy max. 100 tickets for that event (or whatever you set). That can be 100 pcs from one ticket, or a total mix.
Let me know if this is what you are looking for.
Cheers,
Andras