It would be great if we could apply either user macros or inventory items at the Host Group level. This furthers Zabbix's use as a CMDB, and greatly improves the ability to customise all aspects of monitoring (enables monitoring of host groups as an object).

My specific use case is that I discover hosts via Autoregistration or Network Discovery, however have no way of automatically inserting a host inventory item saying that this host is part of "Host Group 1". The only way I can currently obtain that information is via host.get via API, or by inserting an inventory value via API (for example, site_address_a get's the host.get selectGroups value).