It would be awesome that we could have another kind of dependant item in Zabbix. A new kind of dependant item would mean that kid item would act like a normal item, but its refresh would be indicated by the change of its' master item. Having that feature, kid item shouldn't have so tiny refresh interval because it would refresh only on a real update. For example, master item is a Log item in which I grep "Synchronized" word, and kid item would be an HTTP agent that would curl the website and by that collect new content.