As you might know, VMware vSphere Hypervisors are discovering through host prototypes:

And I'm looking for a way to override MACRO for some hosts. For example, {$VMWARE_HOST_MEMORY_WARN} is defined in "Template VM VMware Hypervisor".

First, I tried to do this by defining some macro in the host prototype and then using it within the trigger expression as context, but I failed - not support ZBXNEXT-8678 has been created.

Now I'm trying to use the Override functionality https://www.zabbix.com/documentation/current/en/manual/discovery/low_level_discovery#override

And I failed again because there was no option to override MACRO for the host prototype. 

I think there should be an option to define or override MACRO for the host: