Problem with parallel activity/slots

I am using K2 2003.net, and there is no option for user/group. (in "Activity General")

I can only choose between "Create a slot for each destination" and "Limit number of slots to...".

Or am I missing something?

The number of user groups is dynamic (depending on the user input in the previous Activity), so I don't know beforehand, how many Usergroups I need to route it to (it could be anywhere between 1 and 7 usergroups)

But is there a possibility to delete (or complete) one specific slot in K2?

In my example I would like to delete the worlistitem for User 2, when User 1 approves.

Ok, maybe "dynamically" is not the right word... this is what I am doing:

I have an InfopathForm with checkboxes. Depending on which checkbox are checked, I add the destinationgroups to the Infopath XML,

<my:Responsibles>
  <my:Responsible>group1</my:Responsible>
  <my:Responsible>group2</my:Responsible>
</my:Responsible>

Then in the Approval Activity - Destination Rule ("create a slot for each destination"), I read the destination groups from the XML (K2InfopathSchema), like this:

 foreach(XmlNode node in responsibles.ChildNodes) 
 { 
       string adGroup = node.InnerText; 
       string[] userList = ADHelper.GetUsersForGroup(adGroup); 
                        
                       //== sendto
                        foreach(string user in userList)
                        {
                                K2.Destinations.Add(DestinationType.User, user); 
                        } 
    }

This code works and creates a slot for each member of the group.

But as I said, now I want to remove the worklistitem as soon as one member of a group approves, whilst the items remain in the worklist of the other group members

Thanks, Tim!

Point 1) looks promising, but there it won't quite work in my case:

The activity has already been assigned to 4 users in my example User1, User 2 (group1) and User3, User4 (group2)

When User1 has finished the activity, I want the worklist item to disappear from User 2's worklist but it has to remain in User 3 and User 4's tasklist.

So how can I make the worklist item disappear from user 2's worklist? I think it will only disappear, when the ActInstDestination.Status is Completed. But this status field is read-only... otherwise I would set it to complete, once user1 is finished...

So as you suggested, I need a flag with the groupname that I set as soon as one user of a group completes the activity. (So far so good)

But now how do I "tell" the other worklistitems from the same usergroup to complete (or disappear from the worklist)

Thanks for your help,

 Rene