Load new geojson layer clicking on choropleth map

Hi,
I am looking for a solution to load another geojson layer in my choropleth map when clicking on one of the feature from the current geojson layer. The idea is to go from 1 digit postcode to 2 digit postcode and so on.
Here is a snippet of my code. Can I add two callbacks for one figure?

geodata = pd.read_sql(
      """SELECT jsonb_build_object('type','FeatureCollection','features',jsonb_agg(features.feature))FROM (SELECT jsonb_build_object('type','Feature',
 'id', plz1,'geometry',ST_AsGeoJSON(geom)::jsonb,'properties', to_jsonb(inputs) - 'geom') AS feature FROM (SELECT * FROM plz1) inputs) features;""",
mydb,
)


geodata_dict = geodata.iloc[0]["jsonb_build_object"]

# write dict to json
with open("test.json", "w") as outfile:
     json.dump(geodata_dict, outfile)

# read json
 with open("test.json") as f:
      data = json.load(f)

# using view kpi
df = pd.read_sql("""SELECT * from kpi_v2""", mydb)

df = df.rename(
     columns={
    "plz1": "Postcode Region",
    "pue": "Power Usage Effectiveness",
    "erf": "Energy Reuse Factor",
    "wue": "Water Usage Effectiveness",
    "cer": "Cooling Efficiency Ratio",
    "ref": "Renewable Energy Factor",
   }
  )

 OPTIONS = [
"Power Usage Effectiveness",
"Energy Reuse Factor",
"Water Usage Effectiveness",
"Cooling Efficiency Ratio",
"Renewable Energy Factor",
]

   # choropleth map
  @app.callback(Output("my-graph", "figure"), [Input("var_choice", "value")])
     def update_figure(var_choice):
        def genereatecolorscale(text):
           if text == "Power Usage Effectiveness":
               return (1, 3)
           if text == "Energy Reuse Factor":
               return (0, 8)
          if text == "Water Usage Effectiveness":
               return (0, 10)
          if text == "Cooling Efficiency Ratio":
             return (0, 12)
           if text == "Renewable Energy Factor":
              return (0, 1)
          else:
                  return (1, 6)

     range = genereatecolorscale(var_choice)
     fig = px.choropleth_mapbox(
     data_frame=df,
     geojson=data,
     locations="Postcode Region",
     color=var_choice,
     featureidkey="properties.plz1",
     color_continuous_scale="balance",
     opacity=0.5,
     range_color=range,
     mapbox_style="open-street-map",
     zoom=4,
     center={"lat": 51.110924, "lon": 9.682127},
 )

 fig.update_geos(fitbounds="locations")

 fig.update_layout(
    paper_bgcolor="rgba(0,0,0,0)",
    width=400,
    margin=dict(l=0, r=30, t=10, b=10),
    legend_font_color="#31364c",
    font_color="#31364c",
    coloraxis_colorbar=dict(title=""),
)
 return fig

@app.callback(Output("page-content", "children"), [Input("url", "pathname")])
 def render_page_content(
pathname,
):  # pathname is just the / after the port thats why its loading...http://127.0.0.1:8050/
    if pathname == "/":
        return [
          html.Div(
             [
                                dcc.Dropdown(
                                    id="var_choice",
                                    value="Power Usage Effectiveness",
                                    options=[
                                        {"label": i, "value": i} for i in OPTIONS
                                    ],
                                    optionHeight=20,
                                    style={
                                        "background-color": "#121212",
                                        "color": "black",
                                    },
                                ),
                                dcc.Graph(id="my-graph"),
                                html.Label(
                                    "Erläuterung der Kennzahlen:",
                                    style={
                                        "margin-top": "10px",
                                        "color": "#31364c",
                                        "font-weight": "bold",
                                    },
                                ),
                               
                    ],
                    className="row",
                    style={"font-color": "red"},
                )
            ]

Hi @ghibli,

what do you mean?