That is not possible unless you always link all of your records in that view to one record in another table. We call these other tables “utility tables”, because they only exist for the purpose of “hacking” Airtable. In that other table, you would create a field of “count” type that would add up the number of linked records, and then trigger your automation based on that field.
The other alternative (instead of using a utility table) would be to write a Javascript that handles this for you, although I believe there’s a limit on how many records Airtable’s API will return at a time to scripts, so I’m not sure if you’ll be able to get the full count or not. I don’t know Javascript, so I don’t have the definitive answer on this one — someone else would need to answer that problem.
