First you will need to download Process Explorer and run it as administrator: https://technet.microsoft.com/en-us/sysinternals/bb896653.aspx
I have not tested how the bot performs with multiple sessions since my SB key is limited to 1 session only.
Code:
1. go to \Heroes of the Storm\Support64\HeroesSwitcher_x64.exe and launch the game
2. run Process Explorer as administrator
3. select HeroesSwitcher_x64.exe
4. press CTRL + L (shows lower pane)
5. find "\Sessions\1\BaseNamedObjects\Heroes of the Storm Game Application" right click it and select close handle
6. find "\Sessions\1\BaseNamedObjects\Heroes of the Storm IPC Mem" right click it and select close handle
7. go to \Heroes of the Storm\Support64\HeroesSwitcher_x64.exe and launch another session of the game
NOTE: You will need to repeat this process (close the 2 handles) for each new session of the game if you want to launch even more.
I have not tested how the bot performs with multiple sessions since my SB key is limited to 1 session only.