You won't be able to do it with the ACTION_PICK intent option. To implement this, you'll need to use a custom ListView with contacts generated from a query to the contacts content provider.
If you want to use the Intent.ACTION_PICK intent, you'll need to tell the user to pick one-at-a-time.
Also
There are several ways to do this with a custom ListView. The old way (that is compatible with most phones) is a bit lengthy to explain, but luckily there is a good tutorial here describing exactly what you're looking for (contact list with checkbox in a custom ListView).
With API 5 and above, there is a ContactsContract class that can help with getting a list of contacts. For example code on how to use this, look at android's ContactManager sample application, specifically the ContactManager class and the populateContactList() method.
Hope it will be helpfull