WP Customizer select with multiple values for "Designed By"?

I’m trying to figure out if it’s possible to use the Customizer controls to create a “Designed By” dropdown menu, and have it echo out the name of the person/group with their name as a link in the footer. This is what I have in my customizer.php, but I’m not sure how to incorporate a URL:

// Add "Designed by" notification in footer
  $wp_customize->add_setting(
    'powered_by',
    array(
      'default' => 'Group 1',
      'sanitize_callback' => 'sanitize_powered_by',
      'capability'        => 'edit_theme_options',
    )
  );
  $wp_customize->add_control(
    'powered_by', array(
    'section'  => 'footer_section',
    'label'    => __( 'Designed by' ),
    'type'     => 'select',
    'priority' => 8,
    'choices'  => array(
        'group1' => __( 'Group 1', 'ctotheme' ),
        'group2' => __( 'Group 2', 'ctotheme' ),
        'group3' => __( 'Group 3', 'ctotheme' ),
        'group4' => __( 'Group 4', 'ctotheme' )
      )
    )
  );

And I have this in my footer.php:

<?php
   if( get_theme_mod( 'hide_powered_by' ) == false) { ?>
     Designed by <a href="#" target="_blank"><?php echo get_theme_mod( 'powered_by' ); ?></a>.
   <?php } // end hide_powered_by if ?>

Also, in the echo, instead of saying “Designed by Group 1”, it says “Designed by group1″… it’s using the label instead of the value associated with the label and I can’t figure out why. Any help? I’m a beginner to intermediate at PHP. I assume this would be a multidimensional array, but I’m not sure that can be used here.