If you take a look at the manual for the 430 you will see that you can only load one approach at a time.
Turn the large right knob to highlight ‘Load?’ or ‘Activate?’
(approaches only) and press the ENT Key. (‘Load?’ adds the procedure
to the flight plan without immediately using it for navigation
guidance. This allows the pilot to continue navigating the ...
The ground station transmits responses to interrogations
from other aircraft and randomly timed signals that look
just like responses, so an aircraft has to pick responses to
its transmissions out of all the other signals that look
like they could be. The way it's done is by looking at the
ground station transmissions for a while trying to find a
time after ...