tcc/servers/bedrock/definitions/features/nether_soul_sand_underground_feature.json

{
  "format_version": "1.13.0",
  "minecraft:ore_feature": {
    "description": {
      "identifier": "minecraft:nether_soul_sand_underground_feature"
    },
    "count": 12,
    "replace_rules": [
      {
        "places_block": "minecraft:soul_sand",
        "may_replace": [
          {
            "name": "minecraft:netherrack",
            "states": {
            }
          }
        ]
      }
    ] 
  }
}