[REBOL] Linked list in rebol

[tim]

Hello:
        I'd like to implement a *triple* linked list in rebol.
Below is a "c" structure: I'd welcome advice on how
to translate this to a rebol data structure.
If I'm correct, the nxt and prv elements are encapsulated
by a rebol list. What I'd like to figure out is how to
manually reference another node in the list.
(the mrk element)

  typedef struct test_node
  {
    struct test_node *nxt; // points to next node
    struct test_node *prv; // points to previous node
    struct test_node *mrk; // points to a randomly selected node
    long num;
  }TestNode;

Thanks In Advance
Regards
-Tim