Extension Pack for MARI

Where to find it: (This Node is available in the Nodegraph only)

NodeGraph / Right Mouse Click / Add Nodes / Misc / Extension Pack /

The Material Adjustment Multi Channel Node creates a Multi Channel Container where by default the input connections are passed through to the output connections.
Contained within the Subgraph of the Material Adjustment, you can then freely modify individual streams of the material.

In the below example we create a material adjustment for an Unreal Material, open the Subgraph (you can do so by pressing "I"), and modify the Base Color stream.
Changes are nicely contained inside a single node.