Dear Statalist

I am trying to cusotmise a map in stata. I have an EU map with regions at NUTS 2 Level. I want to customise it so that regions in Germany, Belgium and UK are at NUTS level 1, in other words are mega-region.
I understand that there is a mergepoly command and is also inbuilt in maptile.

Please can anyone help if they have come accross a similar problem or at least did something like this.

Your help is greatly appreciated, thank you in advance

Kind regards

Jonathan