WWW.surveyz.com offers the capability to have multiple people complete different portions of a survey that you create.
Here is the Roadmap to allow multiple users to take a single survey:
First Create the survey
Create Branching Breaks at the desired points
For example: If you have a survey with 10 questions and would like the first five questions to be taken by the first respondent -- Create a Branch after Question 5.
Next make sure that Enable Save And Continue is checked in the Survey Administration page.
This will allow the first user to save his response.
Make sure you give instructions to the respondents to Click on Save and Continue after finishing their part of the survey.
Their response will be saved. They can then enter the email address of the next person that needs to finish of the survey with the address to this particular response.
Upon entering the email address of the next respondent, WWW.surveyz.com will send out an email with the address entered requesting them to continue on with the survey.
The next respondent can then click on the link and finish the survey.