2 target languages, same project number - 1st L package works well, 2nd L package nowhere to be found

Hello, please help... I have a bit strange issue when translating the same project into 2 languages (2 separate packages under the same project number). I get two packages (both with English source, one for English-Czech, the other for English-Slovak). The first one I open shows up in the list of projects/files etc., I translate it, save as a return package (and/or as target file), so far no problem. I even mark it as Completed. Then I open the second package and... it is nowhere to be found. It has the same project # but is a different package for the 2nd language. It does not show up in the list separately, or - I see that project number but when I open it, I see the first language that I translated before. Not the new package with empty target segments. I tried everything but was not able to find a solution. Am I not doing something that should be done between the 2 packages? Or do I have to tell the client that they have to create 2 different project numbers otherwise this cannot be solved?

I even tried to delete the first language oroject from the list and when opening the second package, a message popped up that I "already have a directory under this number". I thought a new package would automatically save elsewhere in the Trados directories but apparently not so. So my question is: can I solve it somehow, or does the client have to create the two packages under 2 different project numbers?

Thanks in advance,

Karel