json - Concurrent users Load Testing REST API with CURL command Using Jmeter Tool -

scenario is

1. heroku server sends web service call parse.com using curl command. web services written jason , using rest.
2. i need test performance of parse.com server website in case of 40 users hitting @ 1 time
3. as communication between heroku server , parse.com through rest jason web services assume need generate concurrent 40 calls of each web service hit parse.com.
4. each curl command has 1 user session token , parameters in header configure in jmeter http request when generating loaded web service call
5. i need test scenario in 40 concurrent users simultaneously create project (create project web service) on parse.com (there no web service creating users each curl command has user session token key of each user signed on website)

problem: curl command creating project on parse.com has 1 user session. if enter 40 value in thread. create 40 projects against 1 user session. whereas want 40 users creating 40 project simultaneously.

here curl command 1 user session

curl -x post -h "x-parse-application-id: " -h "x-parse-rest-api-key:" -h "content-type: application/json" -h "x-parse-session-token: l8beiq2zv6kf420nbno8k7or1" -d '{"projecttype":"feedback","users":null,"owneronlyinvite":false,"topicname":"service update topic","name":"service update","deadline":"2014/03/08","s3projectimagekey":"065d417c-eeaa-4e74-bb43-5bdced126a58"}'  

question:

should use curl command in jmeter load testing or there alternative testing rest jason web services. if enter 40 user session tokens in http header while configuring http request in jmeter. hit 40 concurrent users creating 40 projects on parse.com?

this can achieved following steps mentioned below:

• using csv, put session tokens want use in csv file. jmeter use 1 token every user.
  refer: http://ivetetecedor.com/how-to-use-a-csv-file-with-jmeter/

hope help.