Yes, you can.
This feature is controlled at the Venue level within your app.
On the Facebook Venue where you want ads, but not posts on the page, you would simply edit the venue and UNCHECK the Publish box and click save.*
The next time an item is processed through that Venue it will create an Ad with the post, but not make a post on the page.
If you ever want to resume posting to the page, simply come back to the venue, recheck Publish and Save.
*TIP - Unchecking the Publish button may not "Activate" the save button. If it doesn't, there is an easy workaround. Just change the duration number and then change it back ( so change 2 to 3, then back to 2) and you'll be able to click Save.