Create local topographic representations. Don't connect distant sensors in topomap.

Describe the problem

When creating topoplots for montages that have clearly separated clusters of sensors the plotting connects these regions, often creating some visual distortion between regions of interest.

For example in the fNIRS example here I would like the left and right regions repeated. Here is what I would like removed.

And here is another example with a dataset with 4 seperate regions that I would prefer plotted independently

Describe your solution

I am not sure of the optimal solution, but my initial thoughts are I would like to be able to either specify how many independent regions I want plotted. Or perhaps specify a maximum distance between sensors, and anything above this distance is not connected in the plot.

Additional context

I tried varying the existing parameters in the topo plot function, but nothing quite achieves my aim.

Start by reproducing the behavior in the linked fNIRS processing example and locating the topomap plotting entry point used there. Review how separated sensor clusters are connected, then define and test a way to render those regions independently, including the four-region example, with a clear completion criterion for avoiding connections across distant sensors.