This is super easy.
You can use Maya’s UDIM system (turn on UDIM in the File nodes: UV Tiling Mode -> UDIM).
Unfortunately there is no UDIM option in Redshift’s custom normal map node (RedshiftNromalMap), but you can still use the <UDIM> naming convention by typing it manually. After you linked the first image just change the number to <UDIM>.
Useful tip for texture connections:
In Redshift you can also use file nodes for Normal maps, Dome Map (rsDomeLight) and other non Maya’s file node based links:
- Create the file node
- Load your image
- Connect the fileTextureName attribute to tex0 attribute
Simple way to do that is via the Connection Editor: in Hypershade, Shift + MMB Drag and Drop the file node into the other node’s header part).