How to customize share intent in Android?

Now i can use the share intent to open the share dialog

    Intent intent = new Intent(Intent.ACTION_SEND);
    intent.setType("text/plain");
    intent.putExtra(Intent.EXTRA_TEXT, link);  
    startActivity(Intent.createChooser(intent, "Share with"));

but i need the dialog not to appear and share directly to one social network for example (FB or twitter)

any advice how to do that ?