Does a single Zap run in parallel or serially?

I’m getting errors in an integration between Eventbrite and Salesforce where I first do a “Find Record by Query” search for a record in Salesforce using multiple fields to see if the record exists first or not. If yes I update it. If no then I create it. However I’m getting errors back from zaps where at search time the record does not exist but then microseconds later when it tries to create the record it already exists so this step errors out.

It looks like this happens when a family registers a group of people and they reuse the same email address for multiple participants. This is quite common. We use the email address as a unique key but we also allow people to have many email addresses so I need to check all of them before deciding to create a new record. So my zap creates the record for the first person but it looks like a zap for the second person may already be running in parallel and sometimes beat the first zap and create the new record  in parallel thus causing the other zap to fail.

Is it possible to force this zap to act serially instead of running in parallel?

I’m also encountering this same situation in adding members to a campaign where if they exist already I’d like to increment a count on the campaign member but if they don’t I’ll create a new campaign member. In on instant they don’t exist but by the time the zap gets to the next step to create them, they it does exist.