I would recommend looking at why you believe you need to have the data in separate arrays. Can you not simply extract the relevant portion from @accts at the point where you would use one of @acctsN.
If it really is necessary then here is a basic example. This is not scalable and is not intended as a practical solution it just gives you an idea of how it can be done.
use strict;
use warnings;
my @accts = ( 1 .. 10);
my @accts1 = @accts[0..1];
my @accts2 = @accts[2..3];
my @accts3 = @accts[4..5];
my @accts4 = @accts[6..7];
my @accts5 = @accts[8..9];