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 AProject 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:

Manually add a package reference from ProjectB to SomePackage.
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.