We are using Zoho ShowTime to run webinar sessions. People who register for webinars are then pushed to Zoho CRM from ShowTime as Contacts (but we will be shortly updating this to Leads). Then, we use the Sync Services in Campaigns to pull the webinar attendees from CRM to Campaigns for follow-up. If someone has registered for the webinar, but not attended, we have a workflow in Campaigns to send them a 'Sorry you couldn't make it' email. 

However, we've recently noticed that people who have registered for multiple webinars are not receiving the 'sorry' email, except for the first session they registered for. In Zoho CRM, each Contact has every session they have registered for attached to their record in a list under the Zoho ShowTime module. However, in Campaigns the fields that are syncing from the CRM are not being updated with the most recent session they have attended. When the syncs happen, any email address that already exists in Campaigns seems to be going down as a 'duplicate contact' and being ignored. 

What we want is for the relevant field to be updated with the most recent session the person has attended each time. Is this possible to set up or configure?

Thanks.