How to add conditional imports across Flutter mobile,web and window?

I have flutter application which uses different webview plugin for each platform(mobile, web, window).
Though I am able to import platform base on web and mobile, I am not able to import for windows.

I have tried adding else condition if it is not mobile or web, but it is taking mobile plugin.

1. This is how I import package for web and mobile (Working).

import 'package:eam_flutter/form/mobileui.dart'
    if (dart.library.html) 'package:eam_flutter/form/webui.dart'
    as multiPlatform;   

2. This is how I import package for web, mobile and windows (Not Working, it is showing mobile webview exception since it doesn't support desktop).

import 'package:eam_flutter/form/windowui.dart'
    if (dart.library.html) 'package:eam_flutter/form/webui.dart'
    if (dart.library.io) 'package:eam_flutter/form/mobileui.dart'
    as multiPlatform;

How can I specify conditional imports for windows?

For anyone else finding this, note that the accepted answer is not an answer to the question that was asked. The answer to the question that was asked is that you cannot. There is no way to use conditional imports to get different behavior between mobile and desktop; see this comment from the Dart team.