I am using the Napili Salesforce Community Template and I want to modify just the record detail page for a specific custom object. Is that possible? I see how I can go into Community Builder > Page Editor > Record Detail and edit all record detail pages but I don't see how I can edit it only for specific objects such as a myObject__c custom object. Or, alternatively is there a way to re-direct it in the community when it does to that specific page?
Yes, it is possible to modify just the record detail page for a specific custom object, but you'll need to create that page first.
When you are in Community Builder, go to Page Manager > + > Create Object Page > [Choose your Object] > Create. Check the screenshot for the first 3 steps.
Now you can go back to Community Builder > Page Editor > OBJECT_NAME Detail and edit the record detail page layout for only this specific object.
This article should get you your answer - View and Create Record Detail Pages in Napili - releasenotes.docs.salesforce.com
Also, in case you need to customize the record detail further - like to move the field around in the detail layout - create a new page layout in Salesforce for your object and assign it to the profiles which have community access. This new layout will be used when displaying the record detail page.
