C# Conditional Attribute: What about using directives?

Question

I am writing a c# application that currently uses

#if IOS
using Plugin.Firebase.iOS;
#else
using Plugin.Firebase.Android;
#endif

and then it uses it later on:

void SomeMethod(Events events) {
#if IOS
    events.AddiOS( _ => { // AddiOS is only present on the IOS version of plugin library
        // some IOS specific code
    };
#else
    events.AddAndroid( _ => { // AddAndroid is only present on the Android version of plugin library
        // some Android specific code
    };
#endif
}

I just learned about conditional attributes. They seems super powerful and easier to use.

However, when I refactor the call to AddiOS() into its own conditional method using

[Conditional("IOS")]

it gives a compiler error since it can't find Plugin.Firebase.iOS anymore. If I remove the #if for the using directives, I get compilation errors.

Is there a way to attach using directives to conditional methods somehow? A google search didn't turn anything up, but I wasn't too sure what to search for.

Just to add: I can get conditional methods working when they don't depend on packages that need to be imported using #if as well.