A major problem on many servers is issues with some Traders not opening because too many are already open. I'd like to reduce the number of traders to 5, to have 1 of each trader, but I don't see any way to ensure each trader is spawned, as opposed to duplicates of one or more.
My current thought is to move the <property name="spawn_trader" value="true"/> value from roadsides to Cities, so traders always spawn near them, but I need some way to make sure I only get one of each trader ID. Are there additional property values that would allow me to do this? If so, maybe it would be possible to do something like enabling spawning of specific traders in specific biomes (ex: Jen in forest, Bob in wasteland, etc.)