You would need to do that with Integromat instead of Zapier.
Zapier is not capable of doing this because it has very limited Airtable support, but Integromat has full Airtable support — including watching Airtable records for changes and then updating Salesforce as a result of those changes in Airtable.
p.s. I am a professional Airtable consultant and a Registered Integromat Partner. If you have a budget for your project and you’d like to hire an expert to help you set this up, please feel free to contact me through my website at ScottWorld.com.