This join checker lets you implement a multi-instanciated vote according to the veto rule.
You need to add a process variable (text type) where this join checker will store a value if the veto rule matches.
You need to add a step variable (text type) where you will store the answers (votes) of your users.
Then you just have configure the join checker with the name of the step variable + the veto value and with the name of the process variable + the value to be set in case of veto.
Enjoy it.
Repository URL : http://community.bonitasoft.com/project/veto-join-checker