Forum:Choice of PT1 and PT2

so i finished the first playthrough...

now when i started the game again, it asked me to choose between PT1 and PT2. for now, i'm always choosing PT1 because i want to finish the DLC first on that playthrough.

but can i choose PT2 without loosing my PT1-savegame? will they stay seperated or will the original savegame be deleted?! i'd like to play PT2 to level up a bit and then go back to PT1 to continue the DLC-missions... is that possible?