Hi, you might want to check the apps in the Joget Marketplace. Not exactly similar, but the Newsletter Management and Training Evaluation apps there might seem to be suitable starting points for customization.

This is how I'd approach this use-case:

• Create a form with a multi-select box (or any grid or something) populating the list of users.
• A user would select one or many names from the selectbox.
• There would be a processTool plugin after this to instantiate a process definition for all the selected usernames. (Can also be achieved using looping using counterIncrements or something and calling in a subprocess for all the selected users)
• This invoked process would have a form (invitation) for the users to fill and then move on through the process.

There may be other ways of achieving it, but this was just an initial thought I had for the problem.

Hope this would help.

Thanks.