Hello @Grover 
thanks a lot for using our newly introduced Grafana Plugin and for reaching out as well.
So the idea behind the Plugin is to bring the Netdata Overview screen’s functionality to your Grafana Dashboard.
The Overview screen renders composite graphs at the context level for the various nodes that may exist in your room. Whereas a Single Node View resembles the view of your local Agent dashboard rendering one graph per chart.
At this point I can also quote from our docs that a context is a way of grouping charts by the types of metrics collected and dimensions displayed. It’s kind of like a machine-readable naming and organization scheme.
So a context graph (for example net.net) is composed from multiple chart instances (for example net.eth0, net.eth1 etc.) using a grouping function (for example SUM) as seen in this screenshot:
In The Netdata Cloud Custom dashboards a user can add both:
- Composite graphs (like
net.net) that refer to all the nodes of a room
- Single Node View charts (like
net.eth0) for a node of the User’s choice.
The difference with the Grafana Plugin is that it just brings the Composite Graphs query engine as mentioned in the beginning. Note that it is quite powerful though.
So maybe there is a way to achieve the desired result using the filtering capabilities that exist for composite context queries.
The net.net context exposes the device chart label which can be leveraged for filtering. The device chart label is actually exposed by each and every one of the charts composing the context and it carries the value of the actual interface that this chart refers to.
So in your case you could probably configure your Grafana Panel using the Netdata plugin like this:
So you can select only the node you are interested in and then Filter by device where device value equals the desired interface.
As far as the the wmi.* case you mentioned is concerned, maybe there no similar chart labels are exposed by the underlying charts so more detailed filtering may not be available right now.
Nevertheless, we’re working into adding additional filtering capabilities soon. So the user will filter by the desired chart instances that are actually contributing to the context and we’ll update the Grafana Plugin accordingly to take advantage of this new feature.
Ultimately the user will be able to actually construct lower level queries even targeting a specific chart instance of a context.
Hope that all the above made sense, if not feel free to ask additional questions 
