I have a Nikon D5300.

* Mode: Manual
* ISO: 100 (Bright Daylight)
* Aperture: f/5.3
* Shutter:1/80
* Lens: 70-300mm

I am trying to find a way to focus on multiple objects, in my case, a bouquet of flowers. I just want the focus on, lets say 3 roses, and rest is out of focus.
I am in manual mode. I tried setting the focus point to 9, 21 and even 39 points.
Focus mode is set to AF-A or AF-C. Still I could get only that one rose in focus with rest blurred out. 

Is it even possible? Thanks for any advice!