You can only import one iCal link per property into SuperControl directly, however if you need more than one iCal link per property you can use a third-party tool such as Teamup.
What is Teamup?
Teamup provides a central calendar for iCal links that can be consolidated. The free version allows up to 8 other iCal links. You may add as many iCal links as needed with a paid subscription. This calendar can be imported into SuperControl in order to update the availability in SuperControl of those linked calendars.
Teamup has provided specific documentation on setting up multiple iCal links for SuperControl: https://calendar.teamup.com/kb/how-to-use-teamup-to-consolidate-ical-feeds-for-supercontrol/
It is advisable to upgrade to a paid plan for more frequent refresh of the feeds. See the available options