Can I build multiple projects on one build machine at the same time?

Development Platform & Builds
1

I am in the process of preparing to be able to build UE projects on a CI environment.

With the following commands, the build can now be performed successfully.

Engine/Build/BatchFiles/Build.bat TestProject Win64 Development -Project='TestProject.uproject'

However, when I run two of these at the same time, one of them gives me the error “A conflicting instance of UnrealBuildTool is already running.”
(of course the directory is duplicated and references another path uproject)

Can I build multiple projects on one build machine at the same time?

I’m using Unreal Engine 5.3.2.

2

I read and understood the source code.
If I add -WaitMutex, it waits, and if I add -NoMutex, it can run in parallel without waiting.

However, on that machine, a build using “Engine/Build/BatchFiles/RunUAT.bat BuildCookRun” may also run at the same time.
Is there any way to pass -WaitMutex when UAT uses UnrealBuildTool?