Label input/output blocks

[Gistbatch]

Is your feature request related to a problem? Please describe.
When conducting experiments one might be interested in only some of the outputs and their related observables. To associate this it is necessary to distinguish in and output blocks.

Describe the solution you'd like
First specifying a set of blocks corresponding to outputs, any remaining open node will therefore be marked as input.
From this set, select one output and run only the experiments of correlation surfaces connected to that output.

Describe alternatives you've considered
I think there's no good alternative, we cannot always figure out where in and outputs are, e.g. in the 3 CX example.

Additional context
Figure of the 3 CX example