NodeProxies with different numbers of inputs vs outputs

I’m working with ATK or HOA, so when doing source encoding, I’m taking mono (or stereo) sources and encoding them to ambisonic form (e.g. 3rd order, which requires 16 channels, or 4 channels for 1st order). I think the usual “convention” would be to create a NodeProxy with the required number of output channels, and just use the first one/two of those as (mono/stereo) input, and output the 16 encoded channels as usual. But is there a way to explicitly have different in vs out size? With Synths, of course I can just In from a Bus with two channels and Out to a bus with 16…is there a way to do something equivalent with NodeProxy? (I’d love to use Ndef to help manage these things conveniently for live-coding, and easy patching of connections).

Update: After further investigation, I’ve found that this more or less works:

// Make a mono source
Ndef(\src, { *, 0.1, 1.5) });
// Encode with to 3rd-order ambisonics (1 in, 16 out)
Ndef(\encode, {, \,,45).degrad, 0.degrad, 0, plane_spherical: 1, radius: 2) });
// Map the source to the encoder's input
Ndef(\encode) <<> Ndef(\src)
// Decode to binaural stereo (16 in, 2 out)
Ndef(\decode, {, \!16), hrir_Filters: 1) });
// Map the encoded source to the decoder
Ndef(\decode) <<> Ndef(\encode)
// Play the result... (don't really need to state 2 channels here,
// since \decode is a 2-channel NodeProxy, but just to be explicit...
Ndef(\decode).play(out: 0, numChannels: 2);

Two things with this – I’d like to output multiple sources to the decoder, so it needs a 16-channel bus of its own. I guess I could create another NodeProxy “in the middle” just to receive all the sources.

The other issue, if I try to remap (e.g. a different source to the encoder), it doesn’t work:

Ndef(\anotherSrc, { var n = 8;, 1), * *!n).range(0.7,1.4), 0.8, 0.2 / n.sqrt).sum });
Ndef(\encode) <<> Ndef(\anotherSrc)
// WARNING: Could not link node proxies, no matching input found.

Thanks for any suggestions,