Try something like this:

>perl -wMstrict -le
"my %employees;
 my @values = ('value1', 'value2', 'value3');
 @employees{ qw(key1 key2 key3) } = @values;
 print qq{ @{[ %employees ]} };
 my $hashref = \%employees;
 @{ $hashref }{ qw(key1 key3) } = qw(foo bar);
 print qq{ @{[ %employees ]} };
"
 key2 value2 key1 value1 key3 value3
 key2 value2 key1 foo key3 bar
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Note the critical syntax is @{ $hashref }{ qw(key1 key3) } = qw(foo bar);.