swaping objects into different simsets keeping simset position

Hi,

I´m struggling my mind unsucessfuly to achieve this goal:

I have 2 columns, each one being a simset, containing several items, I´m swaping both items in the position number 4, but that means remove each one from its simset while adding to the new one, going from simset 1 to 2 and viceversa, but they dont keep its order inside the new simset. I have tried reorderchild to solve this, but I can´t.

Can somebody give a hand with this problem please?

Thanks in advance!