Channel Visibilty Agents bug?

When audio tracks are bused to groups, and those groups are bused to another Group, the option “Show Channels that are Connected to the First Selected Channel” does not display the “downstream” group.

Example:
I often multi mic strings with the audio tracks bused to a group “Strings 1”
Then I add another layer of strings with the audio tracks bused to “Strings 2”… Then “Strings 3”…etc. (To have control of each layer as a group.)
I then have all these groups bused to another group “STRINGS ALL” (for control of all the strings).

But if i select an audio track that is routed to “Strings 1” and chose “Show Channels that are Connected to the First Selected Channel”, Nuendo correctly shows me the connected tracks, (including FX returns and Master output), but does NOT display the “STRINGS ALL” group. It somehow misses groups that are routed from other groups.

Is this the intended behaviour? Or a bug?