Ignore the input keys, split each value on its first "|", collect all unique preceding numbers hashed by following string.

foreach (values %in)
{
    /(.*?)\|(.*)/;
    $out{$2}{$1} = 1;
}
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Convert %out values from hash ref to array of keys

foreach (values %out)
{
    $_ = [sort keys %$_];
}
# $out{"RED DOOR|10-14"}[0] = 73 etc
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I'm assuming there may be repeated values in the input but you only want each number once per key in the output.