Linking parameters across Ndefs

Hi List,

How would I go about linking parameters of separate Ndefs so that,
for example, setting the \freq argument in Ndef(\a) also changes the \pan
argument in Ndef(\b)?
I know it's possible to use a bus (or a third Ndef which can double as an
LFO) and map that to the two other Ndefs, but I am wondering if there is a
better/more convenient method.

Thanks!