I have a solution with a number of projects in it. Even if I set the web project\'s start options to:
To extend @Aleksey L.'s answer, you can actually do this with a plain text editor like Notepad.
In your projectname.csproj.user file, make sure your the AlwaysStartWebServerOnDebug node has a value set to False.
projectname.csproj.user
..
False
..
Alternatively, to do this without a text editor you can use Powershell
$file = 'projectname.csproj.user'
$x = [xml] (Get-Content $file)
$x.Project.ProjectExtensions.VisualStudio.FlavorProperties.WebProjectProperties.AlwaysStartWebServerOnDebug = 'False'
$x.Save($file)