That wouldn't be 1:1, just plain outbound NAT (Firewall > NAT, Outbound tab)
Switch to hybrid outbound NAT and add rules to do just what you state, for example:
Interface: WAN
Protocol: Any
Source: Network, 192.168.2.0/24
Destination: Any
Translation Address: 1.0.0.2
And then repeat that, changing the source network and translation address. You'll need one rule for each pairing.