how can i make tree from two different tables?

include_once’…/common/db_con.php’;
require_once("…/connector/db_postgre.php");
require_once("…/connector/tree_connector.php");
$conn = get_db_connection();

$group = new TreeConnector($conn,“Postgre”);
$domain = new TreeConnector($conn,“Postgre”);

//parent nodes table
$sql = “select * from mds_group_info order by p_group_id”;
$group ->render_sql($sql,“group_id”,“group_name”,"",“p_group_id”);

//leaf nodes table
$sql = “select seed_id, alias, group_id from seed_domain where group_id = 1”;
$domain->render_sql($sql,“seed_id”,“alias”,"",“group_id”);

how can i make tree from two different tables?
The level of the child node is flexible.
so I can not use MultitableConnector

Before considering the use of insertNewChild function(client-side),
I would like to add a child tree using TreeConnector(server-side).

You may try to use the render_complex_sql method to load the data from several datatables:
docs.dhtmlx.com/connector__php__ … complexsql