Actually it is not possible to have an Import IQL Filter that is using information based on reference objects. It is needed to filter object by reference during the import

for example:

just import host system where the reference operating system.name like windows

It is needed to add the possibility to add references with an IQL that using object references

for example:

Importing a network device which contains a list of "connected" mac addresses

these should be linked to host systems where the mac address information is available in a list of Networkintefaces. So the mapping IQL would be something like "Host".Networkinterface"."Mac Address" In (${MAC Address{0}})