From WEBi only?
Is this a recurrent job, or something exceptional?
If it is exception, then a CMOD admin could do it with some "arsdoc get" command, merge the result and give it to the user.
If this is something "normal", then I know something like that could be done with the successor of WEBi, which is ICN, because you can write a Plugin for it, and do whatever you want, if you know how to code in Javascript/Java/HTML/CSS.
Now with WEBi, I know there are some Javascript APIs... but I have no idea how to do what you describe, and if it is possible to add this functionality. Probably yes, but I have no idea how...