Using opportunity/product information to filter related leads/contacts

Using opportunity/product information to filter related leads/contacts

Sorry if this has been asked before but I haven't found anything specific.

I'm doing my initial experiments with Zoho CRM and I'm trying to filter leads and contacts for mass mailing, using data from opportunities or products.

Examples:

-I want to send an email to all contacts that have purchased a certain product.
-I want to send an email to all contacts that have an open opportunity fulfiling certain criteria.
-I want to send an email to all invites in an event.

Is there any way to do this? Leads and contacts can be filtered only using fields from leads, contacts and accounts, I can't find the way to filter contacts with opportunities or contacts with products.

Being able of sending an email to past purchasers of a product is a feature so fundamental to a CRM that I can't possibly believe that Zoho doesn't allow it. What's the point of relating one module to another if you can't use it for searching and filtering and listing?

Thanks!