IdentityServer 4, OpenIdConnect redirect to external sign-in url

I am trying to build multiple small ASP.Net core Mvc services that connect to a Identity server built using IdentityServer4.

I have setup the OpenIdOption on the MVC services that looks like this

app.UseCookieAuthentication(new CookieAuthenticationOptions
{
    AuthenticationScheme = "Cookies"
});

app.UseOpenIdConnectAuthentication(new OpenIdConnectOptions
{
    AuthenticationScheme = "oidc",
    SignInScheme = "Cookies",

    Authority = "http://localhost:5000",
    RequireHttpsMetadata = false,

    ClientId = "mvc",
    ClientSecret = "secret",

    ResponseType = "code id_token",
    Scope = { "api1", "offline_access" },

    GetClaimsFromUserInfoEndpoint = true,
    SaveTokens = true
});

where http://localhost:5000 is the endpoint on which my Identity server is running. say if my MVC server is at http://localhost:5002 I see that when I set a [Authorize] attribute to the controller, it redirects to my identity server and if the check fails, it looks for the signin page back at http://localhost:5002/signin-oidc

Now the issue I have is that I wan the login page to be hosted by my Identity Server hosted at http://localhost:5000/signin-oidc so that all the MVC services just make use of this to get user identity, but unfortunately I am unable to see how to set this RedirectUrl.

I know the diagram is inaccurate in how it works with reference to the flow, just trying to simplify what I want to accomplish :)

is it possible to accomplish this ?

Regards Kiran