Johan,
The answer depends on how far into your build you are, and the complexities up/downstream, as there might be an alternative way.
One way to manage this might be to retain the New Joiner list within a single parent list; such that your hierarchy looks thus:
All Staff
> Existing Staff
>> Staff 1
>> Staff 2
> New Joiners
>> Staff 3
>> Staff 4
This way you eliminate the need to "delete" from the New Joiner list, and would utilise the status field (I'm guessing someone needs to either choose "Employee" from a drop down as status, or tick a box to state no longer New Joiner), and from there you run the import and simply set the status as the parent - thereby moving within the structure, as opposed to copying to an entirely separate list. Of course you can then subset and utilise each branch in your downstream as needed.
However, if do you need to keep it this way, perhaps consider utilising a few line items to work out which codes overlap, and if we have a match then set up a boolean filter against which you can run the "Delete from list using selection" method.
Something like in module 1 which contains the list of New Joiners
Staff 1 - code 00123
Staff 2 - code 00124
Copy across to the "Employees" list using code as the unique identifier (and utilising any other flags/filters telling us which records need copying), you'll then have these two items appear in both lists.
You can set up a module which is dimensioned by "Employees" List, which simply contains the code, and a finditem line item:
finditem(New Joiners List, Employee Code)
Where there is an overlap this will produce a positive result, against which you can set up an if then else boolean, and use this to delete.
Pop both actions into a process and then you should be able to copy across, identify entries which exist in Employees who also exist in New Joiners, and delete from New Joiners
Hope that helps?
