Priority Activation Group - Revert back to top group

Hi,

Complete newbie question here.

I have a pool with 4 nodes as per setup

Node 1 - PAG 100

Node 2 - PAG 100

Node 3 - PAG 50

Node 4 - PAG 50

When we have Node 1 & 2 Down, Node 3 and 4 display a site offline page, which works great.

When Node 1 and 2 come back online, we are still using node 3 and 4, not so great.

I have also tried to get around this by removing nodes 3 and 4 and creating a 2nd pool with them, then using the following iRule

when HTTP_REQUEST {

  if {[active_members [LB::server pool]] < 1 } {

    pool Pool-2

  }

 }

Now the VIP does have a cookie insert persistence profile, which i think may be where i am getting stuck

What would be the best way to do this, without loading the page into iFiles.