hi, i'm trying to do a survey with eight different groups of questions. But i want that a person choose a group one of the groups and answers only the questions inside it.

Can i do this?

So you have, let's say 5 groups of questions. Out of those 5 groups you want your respondent only respond to one?

You could create a list(radiobutton) style question with the 5 groups. Your respondents choose which of the groups they want to answer and based on this you create a question relevance to show or hide the question groups, based on the code of the answer.

For example:

1- What is you department?
A , B, C or D

if A - the respondent will answer certains questions.
if B - the respondent will answer different questions of A.
if C - the respondent will answer different questions of A and B.
if D - the respondent will answer different questions of A, B and C.

Hi,
Browse the manual about group relevance