Drake: Add weld joint to world in SDF instead of after parsing (pydrake)

I have a Kuka arm fixed to a representative table via a simple SDF and I'd like to weld the table to world with a given offset within the SDF rather than after parsing the model. (I've tried to leverage the drake:parent tag to make the table a child of the world frame, but this changes nothing.)

Does this functionality exist?
Current SDF:

<?xml version="1.0" ?>
<sdf version="1.7">
  <model name="iiwa_and_table">
    <include>
      <uri>package://drake/manipulation/models/iiwa_description/urdf/iiwa14_spheres_collision.urdf</uri>
      <name>robot</name>
      <pose>0 0 0 0 0 0</pose>
    </include>
    <include>
      <uri>src/mast/descriptions/sdf/table.sdf</uri>
      <name>table</name>
      <pose>0 0 -0.5 0 0 0</pose>
      <!-- <drake:parent>world</drake:parent>-->
    </include>
    <joint name="static_joint" type="fixed">
      <parent>table::table</parent>
      <child>robot::base</child>
      <pose>0 0 0 0 0 0</pose>
    </joint>
  </model>
</sdf>

My current method for welding the table in a particular position is as follows:

builder = DiagramBuilder()
self.plant, self.scene_graph = AddMultibodyPlantSceneGraph(builder, time_step=0.001)
resource = FindResourceOrThrow(<path to my SDF>)
Parser(self.plant, self.scene_graph).AddModels(resource)

self.model = get_model_by_name(self.plant, name="robot")
self.weld_model = get_model_by_name(self.plant, name="table")
self.plant.WeldFrames(self.plant.world_frame(), self.plant.get_body(
                self.plant.GetBodyIndices(self.weld_model)[0]).body_frame(), RigidTransform(RotationMatrix.Identity(), [0, 0, -0.5]))

def get_model_by_name(plant: MultibodyPlant, name: str) -> ModelInstanceIndex:
    for idx in range(plant.num_model_instances()):
        model = ModelInstanceIndex(idx)
        if name in plant.GetModelInstanceName(model):
            return model
    raise Exception (print('Model name not found'))

Solution

Yes, this is supported. You just need to add the fixed joint in the SDF and reference the world body and sdf body... as in this example. I believe this adaptation should work:

<?xml version="1.0"?>
<sdf version="1.8">
  <world name="SimWorld">
    <include>
      <uri>model://simple_robot1/</uri>
    </include>
    <include>
      <uri>model://simple_robot2/</uri>
    </include>
    <model name="weld_models">
      <include>
        <uri>model://simple_robot1/</uri>
      </include>
      <include>
        <uri>model://simple_robot2/</uri>
      </include>
      <joint name="weld_robots" type="revolute">
        <parent>world</parent>
        <child>robot2::base_link</child>
        <axis>
          <xyz>0 0 1</xyz>
        </axis>
      </joint>
    </model>
  </world>
</sdf>