Maybe you can explain to us how you need to handle the multiple values.

Should the first value be kept?

Should the last value be kept?

Should all values be kept?

Should no value be kept because it is not clear which value is the correct one?

What should happen if there is more than one value?

What should happen if there are more than two values?

Maybe you want to learn about Perl Data Structures, especially Hashes of Arrays?