I am working with the camera focus settings

I can not get what I need.

I wish were in perfect focus objects A and B but not the object C.

If I set focus well on A, i lose focus on B

If I set focus well on B, i lose focus on A

i can't have A and B at the same distance, but they are really close

can someone help me

thanks

Poser Pro 2014 SR 1 on Windows 7 64 bit
I use IDL, Gamma Correction and EZSkin for all final renders.