<ItemGroup>
        [Do following pattern for each CPI file]
        <None Include="MyCPI.CPI">
            <FileType>CppHeader</FileType>
        </None>
    </ItemGroup>

<Filter Include="Include Files">
      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
      <Extensions>cpi</Extensions>
</Filter>

<ItemGroup>
    [Do following pattern for each CPI file]
    <None Include="MyCPI.CPI">
        <Filter>++Include Files</Filter>
    </None>
</ItemGroup>