How can I run a grunt task from within a grunt task?

Here’s an example of manually configuring a task within a task and then running it.

https://github.com/gruntjs/grunt-contrib/issues/118#issuecomment-8482130

 grunt.registerMultiTask('multicss', 'Minify CSS files in a folder', function() {
        var count = 0;
        grunt.file.expandFiles(this.data).forEach(function(file) {
            var property = 'mincss.css'+count+'.files';
            var value = {};
            value[file] = file;
            grunt.config(property, value);
            grunt.log.writeln("Minifying CSS "+file);
            count++;
        });
        grunt.task.run('mincss');
    });