You can enter multiple public Google Calendar IDs into the app, separated by commas.
( genuflectnet@gmail.com,mycatholic.life_6edgf1f10bgli159mgs4uc0r90@group.calendar.google.com )
Open Google Calendar
Go to https://calendar.google.com and sign in with your Google account.
Find the Calendar List
On the left side, you’ll see a list of your calendars under “My calendars.”
Open Calendar Settings
Hover your mouse over the calendar you want the ID for.
Click on the three dots (⋮) that appear next to the calendar name.
Choose “Settings and sharing.”
Scroll to the “Integrate calendar” section
On the settings page, scroll down until you see “Integrate calendar.”
Find Your Calendar ID
You’ll see a box labeled “Calendar ID.”
It will look something like:
6edgf1f10bgli159mgs4uc0r90@group.calendar.google.com