My goal is to import an arbitrary sequence of UDIM textures (diffuse, roughness, etc) and create 2x2 mosaics as a diagnostic daily for lookdev to use downstream.

Currently, I importing the textures with a file pattern top and then capturing the @maptype with an attributefromstring top. I then partition the files by @maptype. How can I use a copnet to mosaic the textures into 2x2 grids even if the UDIM's are not necessarily sequential (ie, there may be missing UDIMs depending on the asset/uv layout)?

I have attached a generic hip file that attempts to approximate the issue.