Ken already gave a practical answer. I want to add that the idea of "exporting to a particular host" his wrong thinking. You cannot do that -- it is inherent in the nature of exported resources that each is available for import by any node. What you can do, as Ken demonstrated, is associate data with your exported resources that allows collectors to be appropriately selective about which to collect.
More generally, it is valuable for maintenance and flexibility of your site configuration for your declarations to be descriptive rather than prescriptive. That is, you should declare the characteristics of your resources (such as that they are members of certain groups) rather than their intended use (such as that they be collected by a specific Nagios server). The use follows from the characteristics; it is not the primary consideration.
John