can opt.relative more specify?

[Rockergmail]

My Expectation：

-src
    -tpl
        -tplA
            -index.html
            -index.css
        -tplB
            -index.html
            -index.css
            
// Example - tplA            

// index.html
<!-- inject:style:css -->
<!-- endinject -->
<p>Content Here</p>

// index.css
.test{color:red}

After Gulp：

-dest
    -tpl
         -tplA
             -index.html(injected index.css)   
         -tplB
             -index.html(injected index.css)
             
// Example - tplA
// index.html
.test{color:red} /*injected tplA index.Css only*/

<p>Content Here</p>

// The same as tplB、tplC、tplD...

But ...

gulp.task('inject', function(){
    gulp.src('./src/**/*.html')
            .pipe(inject(gulp.src('./src/**/*.css'), {
            relative: true, 
            starttag: '<!-- inject:style:{{ext}} -->',
            transform: function(filePath, file) {
                return "<style>\n" + file.contents.toString('utf8') + "\n</style>";
            }
        }))
        .pipe(gulp.dest('./dest'))
});

Although the relative option is fired, but it will include all tpls‘ css files, but what i want is just tplA's. What can i do ?

Respect.