I am afraid, you need new build template to pass additional arguments to the template.
But if you are trying to Publish the build output to different directory based on different Project, you can achieve it by setting up same publish profile for each project. Add publish profile for each Project with same name. you can use File system Publish Method to Publish the output to different directories for each project. Just call the Publish profile in the MsBuild Argument.
/p:DeployOnBuild=true;PublishProfile=Dev