An android app that detects outbound phone calls

For a small Proof of Concept (PoC) I need a working prototype of an Android app that integrates with the "calling" functionality of Android devices. The app should integrate with the calling function. When a user enters a number and presses the "Call" button, a menu should appear. Based on the menu-item that the user then selects a different number should dialed. E.g. the user enters +1 1234567, an menu should pop up showing the items "amerika", and "europe". Selecting "europe" should then display a second menu containing "england" and "germany". Then: - Selecting "amerika" should initiate a call to +1 1234567. - Selecting "england" should initiate a call to +44 1234567. - Selecting "germany" should initiate a call to +49 1234567. There are a lot more features to be included (e.g. slick menu designs etc), which would be developed when the PoC is successful, but this should really be a simple/basic version.