Add dependencies of reference projects to NuGet package

I'm using dotnet pack command for creating a NuGet package for the following scenario:

The projects structure:

Project B
|----> Project A

Project A
|----> SomePackage

I want to create a single NuGet package the contains ProjectB.dll, ProjectA.dll, and SomePackage as NuGet package dependency.

In order to include ProjectA.dll as part of the NuGet package (and not package dependency), I used the following solution that suggests here.

In ProjectB.csproj:

  <ProjectReference Include="ProjectA.csproj" PrivateAssets="all"/>

  <PropertyGroup>
    <TargetsForTfmSpecificBuildOutput>$(TargetsForTfmSpecificBuildOutput);CopyProjectReferencesToPackage</TargetsForTfmSpecificBuildOutput>
  </PropertyGroup>
  
  <Target Name="CopyProjectReferencesToPackage" DependsOnTargets="BuildOnlySettings;ResolveReferences">
    <ItemGroup>
      <!-- Filter out unnecessary files -->
      <_ReferenceCopyLocalPaths Include="@(ReferenceCopyLocalPaths->WithMetadataValue('ReferenceSourceTarget', 'ProjectReference')->WithMetadataValue('PrivateAssets', 'All'))"/>
    </ItemGroup>

    <!-- Print batches for debug purposes -->
    <Message Text="Batch for .nupkg: ReferenceCopyLocalPaths = @(_ReferenceCopyLocalPaths), ReferenceCopyLocalPaths.DestinationSubDirectory = %(_ReferenceCopyLocalPaths.DestinationSubDirectory) Filename = %(_ReferenceCopyLocalPaths.Filename) Extension = %(_ReferenceCopyLocalPaths.Extension)" Importance="High" Condition="'@(_ReferenceCopyLocalPaths)' != ''" />

    <ItemGroup>
      <!-- Add file to package with consideration of sub folder. If empty, the root folder is chosen. -->
      <BuildOutputInPackage Include="@(_ReferenceCopyLocalPaths)" TargetPath="%(_ReferenceCopyLocalPaths.DestinationSubDirectory)"/>
    </ItemGroup>
  </Target>

The issue:

When I run dotnet pack ProjectB.csproj I'm getting a single package the contains ProjectA.dll and Project B.dll, but without a dependency to SomePackage.

The question: How do I add the dependency to SomePackage to ProjectB NuGet package?

Possible solutions:

1. Manually add a package reference from ProjectB to SomePackage.
2. Create ProjectB.nuspec file and manually add the dependency to SomePakcage.

The disadvantage of the 2 approaches: I will need to add the dependency for every NuGet package that ProjectA use, which is very easy to forget and breakable.