While absolute positions (like POS=1, POS=2, ...) "start counting" from the beginning of the page, relative positions (like POS=R1, POS=R2, ...) search for matching HTML tags starting from the element that the last successful TAG referred to.
The folllwing macro would thus select the table's field, and then follow the next link to "mydomain" that comes after that table's field (e.g. in the next field)