src/Validation/AbstractValidators.php
protected function relationshipRules($record, string $field): array
    {
        return collect($this->rules($record))->filter(function ($v, $key) use ($field) {
            return Str::startsWith($key, $field);
        })->all();
    }
protected function relationshipRules($record, string $field): array
    {
        return collect($this->rules($record))->filter(function ($v, $key) use ($field) {
            return Str::startsWith($key, $field);
        })->all();
    }
Get validation rules for a specified relationship field.

@param mixed $record
@param string $field
@return array