How to display only members of a specific group?

Can someone please help me?

I have this code:

function jwa_get_top_dino_users( $post ){
global $wpdb;
$post_id = $post->ID;
$results = $wpdb->get_results( "SELECT * FROM " . jwa_get_table_name() . " where dino_id = '$post_id' ORDER BY boost_sum DESC LIMIT 10" );

$data = "<div class='jwa-grid-row jwa-single-post'>
<div class='col-box-12'>
<div class='jwa-grid-row'>
<div class='col-box-6'>
<img src='".get_the_post_thumbnail_url( $post, 'full' )."' class='img-box' style='float: right; margin-right: 30px;' alt='".esc_html( get_the_title( $post ) )."' />
</div>

<div class='col-box-6 jwa-single-post-data'>
<div class='jwa-sub-title'><strong>The most powerful ".get_the_title( $post )."</strong>:</div>";

$n = 1;
foreach ( $results as $key => $value ) {
// code...
$user_id = $value->user_id; // custom type post id
$dino_id = $value->dino_id; // custom type post id
$level_boost = $value->level_boost; // user levels
$health_boost = $value->health_boost;
$damage_boost = $value->damage_boost;
$speed_boost = $value->speed_boost;
// $username = bp_core_get_username( $user_id );
$username = get_user_by( 'id', $user_id )->display_name ;

$data .= "<div style='margin-left: 10px; padding-bottom: 5px'>$n. ".jwa_strong( $username )."</div>";
$n++;
}

Code (markup):

Working with buddypress, is it possible to display the $username of the users that are only members of two specific groups?

bp-groups&gid=2
bp-groups&gid=5

I have found the following code, but I don’t know how to apply:

$this_id = bp_get_group_id();
echo "group id is: " . $this_id; // make sure there is a value here.
$has_members_str = "group_id=" . $this_id;
if ( bp_group_has_members( $has_members_str ) )

Code (markup):

Thanks in advance