Need to update Transportation Zone Hierarchy through program.

My requirement is to create transportation zone hierarchy tree with 5 child through program for tcode : /SAPAPO/RELHSHOW.

I created hierarchy through FM : /SAPAPO/REL_CREATE but i m unable to update hierarchy tree with child node from FM : /SAPAPO/RELH_CHANGE.

Please suggest how can i append child node to Transportation Zone Hierarchy.

Thanks.