How to split a file into multiple files using powerhell based on the values in a fixed position of each row of data in the file

i have file split multiple files.  the data in file fixed width data file.  i split seperate files record code 3 characters stored in first 3 characters in each line.  the data file this:

maindatafile.txt

001datadatadatadatadatadatadatadatadatadatadatadatadatadatadata

001datadatadatadatadatadatadatadatadatadatadatadatadatadatadata

002datadatadatadatadatadatadatadatadatadatadatadatadatadatadata

003datadatadatadatadatadatadatadatadatadatadatadatadatadatadata

003datadatadatadatadatadatadatadatadatadatadatadatadatadatadata

004datadatadatadatadatadatadatadatadatadatadatadatadatadatadata

i record code 001 rows in file called 001.txt, 002 rows in file called 002.txt, etc.  would able pass the maindatafile.txt file name script when run if possible.

fwiw

$filename = 'maindatafile.txt'      get-content $filename |    foreach {    $_ | add-member -membertype noteproperty -name code -value $_.substring(0,3) -passthru    } | group code |    foreach { $_.group | set-content "$($_.name).txt" }

---

[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "

Windows Server  >  Windows PowerShell