stock issue on grouping items

sir,

in previous regime my total transactions (april to june ) maintained by tally erp 9 old version.


after gst implementation...


i created new company period continues said above from (july to onwards ) .


so how to merge two tally data into single dataa..


1. tally data ledgers are created for Vat.

2. ledgers created for GST


so.. how to merge two tally data without losing transactions.


kindly advice......