Q: Unable to view attachments in subscribed iCalendar

I have created a public, shared calendar for my co-workers to use in iCalendar and distributed the subscription via the share link. I have added attachments into the events in the calendar, but my co-workers are unable to download or view the attachments and I am unsure as to what may be the issue. I am using iCal 8.0 and tried adding people privately through their email, but this did not work either.