There is not a setting to hide a body part.
How many records are you sorting? It should not take that long to sort that the objects need to be hid. I would consider limiting my found record set, I don't know of anyone that can view a few thousand items at one time. Since you posted this on the GO forum, I assume you are using this database on FMGo, and large record sets are not wise on ios devices. Ram is limited on these devices and can create all kinds of problem, not to mention it would not be very user friendly.
If you are sorting numbers then limit found set 0 to 999,1000 to 1999, and so on...Maybe even smaller found sets 0 to 99, 100 to 199 and so on...If you are sorting letters limit found set to each letter of the alphabet. such as all As, Bs, Cs and so on.
In FileMaker Pro, duplicate the layout, and then in the duplicate layout, just remove the Body part. This will leave you with just the Sub-Summary part (and possibly Header, Footer, and any other parts). After sorting, go to Preview to determine if this is how you want the printed report.
In some cases, you can replace the body with a subsummary layout part "when sorted by" the table's primary key. If you sort the records where the last field in the sort order is the primary key, the "body" appears. If you sort the records so that this field is not included in the sort order, the "body" does not appear.
I do this in a financial report where the users normally just want to see the subtotals but once in a great while need to see the individual transactions. By clicking a button on the layout, they can toggle back and forth between the more detailed view by a script that changes to the sort order to include or drop out this layout part.