I've got a parent template which contains the following code:

```
{% include '_layout' with {'countryCode': 'au'} %}

```

I have a global set with the handle `au_Variables`, and within that a field with the handle `vimeoVideoId_au`

The problem I'm having is with trying to render the following global: `{{ au_Variables.vimeoVideoId_au }}` dynamically, using the countryCode.

I've tried 

```
{% set videoId = countryCode~'_Variables.vimeoVideoId_'~countryCode %}

```

And then outputting `{{ videoId }}` but all I get is the string `au_Variables.vimeoVideoId_au`, not the rendered global.

Any ideas how to do this in Twig?