How to reuse the same browser in a test suite with Selenium and c#?

Question

Every time a test suite is started the Openbrowser method of the Tbbrowser class is started and a new browser is opened, I wanted to reuse it, it is possible?

ublic class Tbbrowser
{
    public static IWebDriver OpenBrowser(IWebDriver driver)
    {
        string pathWebdriver = ConfigurationManager.AppSettings.GetValues("SP_WebDrivers")[0];
        string nameBrowser = ConfigurationManager.AppSettings.GetValues("SA_Browser")[0];
        string url = ConfigurationManager.AppSettings.GetValues("SA_Url")[0];
        string pathLocalBrowser = string.Empty;

        if (driver == null)
        {
            switch (nameBrowser)
            {
                case "internet Explorer":

                    InternetExplorerDriverService serviceIE = InternetExplorerDriverService.CreateDefaultService(pathWebdriver, "IEDriverServer.exe");

                    driver = new InternetExplorerDriver(serviceIE);
                    break;

                case "internet Edge":

                    EdgeDriverService serviceEdge = EdgeDriverService.CreateDefaultService(pathWebdriver, "MicrosoftWebDriver.exe");
                    driver = new EdgeDriver(serviceEdge);
                    break;

                case "firefox":

                    if (File.Exists(@"C:\Program Files\Mozilla Firefox\firefox.exe"))
                    {
                        pathLocalBrowser = @"C:\Program Files\Mozilla Firefox\firefox.exe";
                    }
                    else
                    {
                        pathLocalBrowser = @"C:\Program Files (x86)\Mozilla Firefox\firefox.exe";
                    }

                    FirefoxDriverService serviceFireFox = FirefoxDriverService.CreateDefaultService(pathWebdriver);
                    serviceFireFox.FirefoxBinaryPath = pathLocalBrowser;
                    driver = new FirefoxDriver(serviceFireFox);
                    break;

                case "chrome":

                    ChromeDriverService serviceChrome = ChromeDriverService.CreateDefaultService(pathWebdriver, "chromedriver.exe");
                    driver = new ChromeDriver(serviceChrome);
                    break;
            }
        }

        return driver;
    }
}

}