SNAT I rule

I have a irule that will read the assigned VIP and assign the same 4th octect to the SNAT address. when CLIENT_ACCEPTED { scan [IP::local_addr] "%d.%d.%*d.%d" lastoctet snat 10.1.91.$lastoctet}

This rule works fine, if a VIP is lets say 10.1.90.100 the irule will set the SNAT address for the internal network as 10.1.91.100. There is a SNAT pool of addresses for this function. My question is how can I make this work for another network if required. Lets say for networks 92 & 93. Do I need to have an absolute in the scan for the subnet I am seeking? I do I simply use the same irule and change the SNAT for the 93 network. Still learning this iRule stuff here.

when CLIENT_ACCEPTED { scan [IP::local_addr] "%d.%d.92.%d" lastoctet snat 10.1.93.$lastoctet}