Printing multiple reports simultaneously


I have an issue while printing reports for multiple sales orders.
When we post two sales order packing slips together(i.e., select 2 open orders and open the packing slip for those orders…check print packing slip report button and print it). we can generate the reports simultaneously. Even I have to print my reports along with those reports. But in my case, one report is prinetd and then second is printed only if the first report is closed.This is happening same as Shipping labels reports in Posting form.

I have no clue how to print them like packing slips. (simultaneously)

Could you please help me in this

Thanking You