Currently we can only configure which types of messages (achievement, server start, etc.) are sent to Discord depending on which dimension they happen in.

I suggest adding the ability to define specific settings for each channel in "minecraft":"dimensions" like in "discord":"channels". Exempli gratia:

"minecraft": {
"dimensions": {
"generic": {
"discordChannel": {
"1234567890" : {
"relayAchievements": false,
"relayChat": true,
"relayCommands": false,
...

All the relayX (such as relayChat, relayCommands) takes a boolean value to enable it/disable it or an array of channel IDs.

"relayChat": true

Means all chat messages are relayed to the configured Discord channels.

"relayChat": true

Means all chat messages are not relayed.

"relayChat": [1234567890, 123456891]

Means all chat messages are relayed to those two Discord channels.

relaySayCommand does not seem to take an array? (I get config error on trying to give it an array of channel names)

Yeah, really need it too.