Sort columns B,C,D based on column B then loop to next 3 columns and repeat till last colu

Hi Guy's I am looking for a little bit of help if possible.

I have a worksheet that contain numerous columns of data that has been imported from other worksheets.

The columns start at column B and repeat every 3 columns. The number of columns can vary per worksheet.

The number of rows can also vary within the blocks of 3 columns. (e.g. columns B,C D may have 20 rows. columns E,F,G may have 27 rows etc.)

I have managed to sort the first 3 columns using the code below, but can not work out how to loop through to the next 3 columns and so on until the last column.

Sub sort1()


Range("B21", Range("D" & Rows.Count).End(xlUp).Address).sort Key1:=[b21], _
    Order1:=xlAscending, Header:=xlYes
    
End Sub

I would welcome any help and advice.

Sorry for cross posting but still new at this, please cross find post here
https://www.mrexcel.com/forum/excel-...ml#post4798951

Many thanks
Andy