if(/begin_item/) {
    while (!/end_item/) {
    ...deal with data members here...
    }
}
[download]

If you do decide to roll your own rather than use Parse::RecDescent, this is the sort of thing for which the range operator is useful.

while (my $range = /begin_item/i.../end_item/i) {
    # skip the first and last lines if you want...
    next unless $range > 1 && substr($range, -2) ne 'E0';

    # deal with data member
}
[download]