You should be able to do it with a global match with an alternation in the pattern.

use strict;
use warnings;

my @strings = (
   q{1.2.3AAABB,AAB,AA,AAABBB},
   q{AABB,AAAB,ABBB});

foreach my $string ( @strings )
{
    print qq{$string\n};
    my @elems =
       $string =~ m{ ( \d(?:\.\d)* | A+ | B+ ) }gx;
    print qq{     qw(@elems)\n};
}
[download]

The output is

1.2.3AAABB,AAB,AA,AAABBB
     qw(1.2.3 AAA BB AA B AA AAA BBB)
AABB,AAAB,ABBB
     qw(AA BB AAA B A BBB)
[download]

Cheers,

JohnGG