Tokens are how you can invite “groups” of people to do a survey and control how they do it.
Here is some further information for you to find out how to do it.
tokens is the way limesurvey restricts access to surveys. Tokens are assigned to individual users and this allows that user to login and complete the survey. When they've completed the survey their token is closed and can no longer be used. Read more about it at http://docs.limesurvey.org/tiki-index.php?page=Tokens, or the way to send emails
From: Srineth Priyanka [mailto:firstname.lastname@example.org]
Sent: Monday, 25 June 2012 4:42 PM
Subject: [limesurvey-developers] How create a group
I want to create a group for response only those people to the survey,
How can I do that?