How can we only display cases that are currently in a particular activity?

We have tried using PROCESS EQUALS TO & SOURCE / TARGET ACTIVITY functions to filter and only display these cases, but they fail due to the following...

• The 'current' activity is irrelevant for PROCESS EQUALS as it technically hasn't been reached yet (e.g 'Verify Invoice' is in progress but not actually complete, so it wont appear as a triggered activity in the log)

• There are multiple routes in our process that lead to this 'current activity' that also have many routes out to other activities. This means that both PROCESS EQUALS TO & SOURCE / TARGET ACTIVITIES cant be used to filter out just cases relating to the current activity, as they require singles routes with a clear starting point (Activity 1) and end point (Activity 2) to work effectively, not multiple possible paths.

We also want to calculate how long this case is been in the 'current activity' but run in to the same issues as described above.

Any help on suggested functions to get what we need would be greatly appreciated.

Thanks for your time.