Create Mutiple Folders From Mutiple Filenames

The code below creates multiple folders based on different file names and moves those files into the new folders. For example, files ABC and XYZ are moved into a newly created folder named ABC and XYZ. I want to advance the code to allow slightly different file names to go into a common folder. Example, I want file ABC_rock, ABC_soil, and ABC_water to be put into a folder named ABC still, AND file XYZ_rock, XYZ_soil, and XYZ_water to be put into a folder named XYZ. I do not want a separate folder created for ABC_rock, ABC_soil, and ABC_water.

Dim strOutputLocation As String = "C:Temp"
Dim rootPath As String = strOutputLocation
For Each filepath As String In IO.Directory.GetFiles(rootPath)

[Code]....