You can have discontinuous time ranges by marking up your calendar: you explicitly declare your free times like the morning and afternoon only In the guarded availability mode:
This is how to achieve this.
Block time from your calendar
On your Outlook Calendar, click on the date to create a new event for the times you want to make available for meetings. Set the title of the to "#free" (no quotes). You can also include other text like "#free for office hours" or "Hold for office hours #free" as long as "#free" (no quotes) appears somewhere in the event title. #free MUST be present in the title.
1. Open Outlook Calendar
2. Drag date from the small calendar to create a new event for the times you want to block off. Add a suggestive title, "#free" in our case.
3. Click on the dropdown, mark yourself as "Busy" and make the event recurrent.
4. Click "Save" and you're done. You marked yourself unavailable for meetings during lunchtime.
Here are the same steps for Google Calendar.
Limit availability time ranges with work hours and event templates
For example, instead of accepting meeting invites for whenever people send them, you may block off Monday, Wednesday, and Friday for working on tasks and leave Tuesday and Thursday open for people to schedule meetings.
You can do this by configuring your work hours and further fine-tune your availability for every event template if needed.