Business system change - PI 7.0 to P 7.3

Hello Everyone

We are in the process of  upgrading from PI 7.0 to P 7.3

Now we have two ports - meaning two sld - Different landscape

The objects reside in PI 7.0 - We have three business systems

on this Sld: say port 1000

DEV - ABCD000

In PI 7.3 : port :  2000

In  PI 7.3

DEV - All the ID and IR objects of  XYZD000 is copy from PROD - ABCP000 (PI 7.0)

now in DEV - XYZD000 all my Directory Objects are pointed to  buisness system ABCP000.

I want in to point to XYZD000 automatically . I have more than 300 objects. so changing manually is tough task

We are on dual stack -

is there a possibilty on how to do this.. I am sure there should be some option . 

migration tool - is not an option - tried that already