So there are several nodes called "Sample ..." - for example, Sample Nearest - that can find a point by its attribute "position".

However, I want to search by other attributes, such as Mesh island index.

I am currently struggling with a particular setup:

I am using the UV pack node to pack my meshes in a square. However, my meshes are not single meshes, so I have to use Convex hull or Bound box to create one mesh per object.

Afterwards, I want to obtain an offset that originates from the UV Pack. Since I disabled rotation, this offset should be the same for every point within the same mesh island. However, I am unsure how to retrieve it. I need to search within the meshes to find at least one point with a mesh island index that matches the instance index. How can I accomplish this?

Setup doesn't work, Sample nearest doesn't work with a custom attribute.