my %players;
for (<DATA>) {
    chomp;
    my ($team,$players) = split /=/;
    push @{$players{$_}}, $team for split m!\s*[,/]\s*!, $players;
}

delete @players{ grep { @{$players{$_}} == 1 } keys %players };
    
local $" = ' AND ';
print "$_ IS IN @{$players{$_}}\n" for keys %players;