Helper function to retrieve the group parent User ID of the latest group account a user subscribed to.

my-pmprogroupacct-get-group-parent-id.php

<?php
/**
 * Helper function to get the parent ID of a group account for a given user.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmprogroupacct_get_group_parent_id( $user_id ) {
	if ( empty( $user_id ) ) {
		$user_id = get_current_user_id();
	}

	// Find group member entries for this user, sorted by ID in descending order to get the latest first
	$group_members = PMProGroupAcct_Group_Member::get_group_members(
		array(
			'group_child_user_id' => $user_id,
			'group_child_status'  => 'active',
			'orderby'             => '`id` DESC', // Get the most recent membership first
		)
	);

	if ( empty( $group_members ) ) {
		return null; // User is not a group member.
	}

	$group_member         = $group_members[0]; // Get the latest active group membership.
	$group_id             = $group_member->group_id; // Get the group ID.
	$group                = new PMProGroupAcct_Group( $group_id ); // Get the group object.
	$group_parent_user_id = $group->group_parent_user_id; // Get the group parent user ID.

	return $group_parent_user_id; // Return the group parent user ID.
}