MSBUild Batching Up Items

gistfile1.xml

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">


    <PropertyGroup>
        <DirRoot>$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)'))</DirRoot>
    </PropertyGroup>

    <ItemGroup>
        <TextFiles Include="$(DirRoot)/src/**/*.txt" Condition="'$(Solution)' == ''" />
        <TextFiles Include="$(Solution)" />
        <Folders Include="@(TextFiles->'%(Directory)')" />
    </ItemGroup>

    <Target Name="Clean" >
        <CallTarget Targets="CleanFolders" />
    </Target>

    <!-- Clean -->
    <Target Name="CleanFolders" Inputs="@(Folders)" Outputs="%(Folders.Identity).Dummy" >
        <Message Text="CleanFolder: %(Folders.Identity)"/>
    </Target>

</Project>