I've been able to integrate two partially split peaks as one peak by changing the peak width over that time. It looks like you're trying to do that based on the timed events table in the picture. The change to larger peak width value needs to be before the peak starts eluting. Change it back to the previous value just after the peak finishes eluting.
If you are able to use manual intergration you can make 1 peak under the results layout. Activate the manual integration, click inside the integrated peak, delet it and integrate it manually. You can try to change the 5.418 Fixed peak width to 5.100 or where the peak starts.
I hope it helps