How to change verbosity of the MSBuild task?

I'd like to have a different verbosity for the msbuild project invoked from the commandline, and those invoked by the MSBuild task from within the project. For example:

Inside my.proj:

<Target Name=Foo>
  <MSBuild Projects="a.csproj;b.csproj;c.csproj"/>
</Target>

On the commandline:

msbuild /v:d my.proj

now when the MSBuild task builds the .csproj files, it does it with detailed verbosity as well. However I'd want to build it with minimal verbosity.

I know it is possible to invoke msbuild manually like so:

<Target Name=Foo>
  <Exec Command="msbuild /v:m a.csproj"/>
  <Exec Command="msbuild /v:m b.csproj"/>
  <Exec Command="msbuild /v:m c.csproj"/>
</Target>

or in practice

<Target Name=Foo>
  <Exec Command="msbuild /v:m %(Projectlist.Identity)"/>
</Target>

and this works well off course, but then I cannot get the functionality of the BuildInParallel switch anymore (I do not think it is possible to invoke msbuild from the commandline with multiple projects without them being contained in a solution?)

Update

I went with Ludwo's option: basically create a custom logger that holds two ConsoleLoggers as a member. One has the verbosity passed at command line, the other one is 'minimal'. The logger registers for all events and passes them to one of the loggers depending on whether a csproj file is currently being built or not. Output looks exactly like normal, except it doesn't include thousands of lines from the csproj files.

You have two options (at least) :)

Create one additional msbuild script for building abc projects "BuildABC.proj"
```
    <Target Name="BuildABC">
      <MSBuild Projects="a.csproj;b.csproj;c.csproj" BuildInParallel="true"/>
    </Target>
```
In your parent script execute MSBuild using Exec task and call "BuildABC.proj" with minimal verbosity
```
    <Target Name=Foo>
      <Exec Command="msbuild /v:m /m:2 BuildABC.proj"/>
    </Target>
```
You have to pass explicitly all parent properties needed in the BuildABC project to msbuild /p parameter.
Use custom logger. See this how to do it. In this case you can use your original script:
```
<Target Name=Foo>
  <MSBuild Projects="a.csproj;b.csproj;c.csproj"/>
</Target>
```
In your custom logger do not log anything related to e.g. "a.csproj" project between ProjectStarted and ProjectFinished events where e.ProjectFile == "a.csproj" (to disable diagnostic logging on "a.csproj" project while building parent project with diagnostic verbosity)