#!/usr/bin/perl -w
use strict;

my $input = "abc 456 897 xyz www 789 jkl 0123 456 889 3 4 fhg 123";
print "input=$input\n";

my @nums = $input =~ m/([a-zA-Z]+(?:\s+\d+){1,3})/g;
print "$_\n" foreach (@nums);

#prints:
#input=abc 456 897 xyz www 789 jkl 0123 456 889 3 4 fhg 123
#abc 456 897
#www 789
#jkl 0123 456 889
#fhg 123

print "----\n";
@nums = $input =~ m/([a-zA-Z]+(?:\s+\d+){2,3})/g;
print "$_\n" foreach (@nums);

#prints:
#----
#abc 456 897
#jkl 0123 456 889