Problem with sync the contact from CRM to Zoho campaign

I want to ask about our problem with syncing the contact from CRM to Zoho campaign.

When one user in my account sync contact from CRM to Zoho campaign, this user can see and sync all contact in another user in our account.

So if i upgare my account, can i manage this problem?

And what can i do if i need the private with the contact.

Many thanks