Pool member reselection issues

Currently I am creating a pool for two servers running as active/standby configuration. The active server assigns with higher priority group number and it works fine when initally both servers are up and running. However, when active server goes down, and passive server start taking the traffic, I want traffic persistent on passive server until it is down (looks like disable the reselection), Since when I restart the original active server when passive server still handle the traffic, the LB reselect action will automatically switch traffic to original active server which runs into unexpected problems within application.