Firewall/NAT

I would like to translate IP adresses on the both sides of m0n0wall
My configuration:
- the WAN network is Y1.Y2.Y3.0 /24
- the LAN network is X1.X2.X3.0 /24
- the WAN device address is: Y1.Y2.Y3.2
- the LAN devices n addresses are: X1.X2.X3.n with n different of 2

when I ping LAN devices(X1.X2.X3.n) from the WAN device (Y1.Y2.Y3.2), is it possible that m0n0wall works like the picture attached .
Thanks