API call - Postman - select specific systemProperties - ?fields=

That was a super fast reply. Thanks.
That's interesting... (and slightly depressing)

I used the following call and had success with it;
{{url}}/device/devices/?filter=autoProperties.name:auto.network.names,autoProperties.value:{{deviceIP}}&fields=displayName,id

Which allows me to only target the device with Property1:A. 
If I understood right, that worked only because I don't have two devices with the same IP...
That's rough. I thought I got something to work the way I wanted and now I learn I just got lucky.

I'll probably need to re-read your reply tomorrow morning, when my brain is functional... But it looks like I can't easily achieve what I wanted.
I thought API calls were super versatile.

Note that my initial question is about 'filtering' the result (fields=), not filtering the devices I'm getting (?filter=). Though I guess what you say applies to both.

Thanks again for your detailed reply.