Yup. Just thought the same about this possibility, than checked it and it seems that we really got 3 out of 6 leves in the main city and another 3 leves - in the field.
For example in Ulda and Scorpion Crossing I have different sets of 3 leves for 1 and 5 lvl.
Hope somebody will found this thread in the future and will save some allowances and time.