/n_map                        Map a node's controls to read from a bus

int          - node ID
[
  int|string - a control index or name
  int        - control bus index
] * N

Takes a list of pairs of control names or indices and bus indices and
causes those controls to be read continuously from a global control
bus instead of responding to n_set, n_setn and n_fill commands. If the
node is a group, then it maps the controls of every node in the
group. If the control bus index is -1 then any current mapping is
undone and control reverts to normal.