Single trendline rather than splitting by color/symbol

Hi, I’ve have a scatterplot with trendlines plotted on it, is there any way to only get a single trendline per color group rather than having a separate one for each symbol type. Currently I have 12 trendlines split across the symbol types rather than the 4 wanted.

    #Producing the Scatterplot
    fig = px.scatter(df_filtered,
            x = "run_date,
            y = "Average",
            color="instrument",
           trendline= "ols",
           symbol="manual_check",
           symbol_map = {"False" : "x",
                         "True" : "circle",
                         "N/A" : "circle"}
                    )

This had the closest solution I can find but it didn’t work when I tried it.