Filtering values from Twig for my custom field type

Question

I have a custom fieldtype for Craft which stores its value as an array of Models using AttributeType::Mixed. See below for an example of the FieldType and Model setup

class MyCustomFieldType extends BaseFieldType
{
    public function defineContentAttribute()
    {
        return AttributeType::Mixed;
    }
} 

class MyCustomModel extends BaseModel
{
    protected function defineAttributes()
    {
        return array(
            'url'      => AttributeType::String,
            'category' => AttributeType::String
        );
    } 
}

Then when the value is persisted, it's saved as an array, which Craft natively saves as JSON

$values = [new MyCustomModel(), new MyCustomModel(), ...];

To display the value in Twig I can do something like

{% for item in entry.myCustomField %}
    {{ item.category }}
{% endfor %}

My question is, how can I only display the elements in my field which have a specific attribute value? For example, if I wanted to display only those items with a category of main, where 'category' is an attribute on my model?

{% for item in entry.myCustomField.category('main') %}
    {{ item.category }}
{% endfor %}

Answer 1

Would this help?

Filter Entries by Field Value

Than it would be something like this I suppose (never used it myself):

{% for item in entry.myCustomField.search('category':'main') %}
    {{ item.category }}
{% endfor %}