my %ident_key = ( from => 'team', to => 'team' );
my %recs_key = ( from => 'employee', to => 'employees' );

my %h; # intermediate hash

for ( @$input ) {
	my %r = %$_;
	my $k = delete $r{$ident_key{'from'}};
	push @{ $h{$k} }, \%r;
}

# convert to your desired structure:
my @output = map {
	{
		$ident_key{'to'} => $_,
		$recs_key{'to'} => $h{$_},
	}
} keys %h;