Help connecting two IPSec's through PFSense

[hd_tn]

I got 2 IPSec connections going into PFSense is it possible to get the 2 IPSec's communicating through PFSense?

At the moment I got the following setup that needs to be kept like it is.

Office 1:
Zyxel USG20-VPN <-IPSec Traffic-> PFSense

Office 2:
Zyxel USG20-VPN <-IPSec Traffic-> PFSense

How every I would like the two IPSec's to communitcate through PFSense like this:
Office 1 <-IPSec Traffic-> PFSense <-IPSec Traffic-> Office 2 and vise visa.

I do not want Office 1 and Office 2 to communicate directly they have to go through the PFSense.

I am not sure how to do this so I hope someone can help me out here.