MT5 >>> Arrange 21 charts in 7 columns and 3 rows

 
I have 21 charts open and when I use the Short-Key "Alt-R", they always get arranged into 5 columns, where the first 4 columns have 4 charts in a row and the 5th column has 5 charts in a row. How can I automatically arrange them to 7 columns with 3 rows?