Function find_field_with_variant_sequential_numbered 

pub fn find_field_with_variant_sequential_numbered(
    fields: &HashMap<String, Vec<(String, usize)>>,
    base_tag: &str,
    tracker: &mut FieldConsumptionTracker,
    valid_variants: Option<Vec<&str>>,
    _numbered_tag: &str,
) -> Option<(String, Option<String>, usize)>

Find field values for numbered tags with intelligent routing

Purpose

Special handling for numbered field tags (e.g., “50#1”, “50#2”) that require intelligent routing based on the specific numbered tag and its variant constraints.

Parameters

• fields: HashMap of all parsed fields with position tracking
• base_tag: Base field tag (e.g., “50”, “59”)
• tracker: Mutable reference to consumption tracker for sequential processing
• valid_variants: Optional list of valid variant letters specific to this numbered field
• numbered_tag: The full numbered tag (e.g., “50#1”, “50#2”) for routing context

Returns

Option<(field_value, variant, position)>