Can We have multiple snats assigne dto single VIP.

I think this example could help you:

https://devcentral.f5.com/wiki/iRules.LB_SELECTED.ashx

the pseudo code an exmaple:

assume that you have servers: 1.1.1.100 and 2.2.2.200

when routing to server 1.1.1.100, use snat 1.1.1.1

when routing to server 2.2.2.200, use snat 2.2.2.2

when LB_SELECTED {
   log local0. "LB_SELECTED [LB::server addr]"          
   if { [IP::addr [LB::server addr] equals 1.1.1.100] } {
      log local0. "snat based on pool member"
      snat 1.1.1.1
   }   
   if { [IP::addr [LB::server addr] equals 2.2.2.200] } {
      log local0. "snat based on pool member"
      snat 2.2.2.2
   }
}

if it suite your need, you could revise it accordingly.