perl -lane "push @{$H{$F[0]}},$F[1]}{print map{$_,qq( ---> ),scalar @{$H{$_}},$/,(join $/,@{$H{$_}}),$/,$/}keys %H" data1.txt

0011 ---> 2
Sally
Roy

1122 ---> 2
Brandon
Simson

2233 ---> 1
George