IRule to Re-load Balance

Thx all here is my issue: i have users connecting to application server , then application server connects to database server i have around 50 application servers & 5 database servers application servers connects to databsae server using 1 TCP connection ( for ex if 10 users connected to application server 1 , thsi application server1 will have one connection with DB serving all of them ) Now , 3 of DB servers went down , so all connections went to DB Server1 , when the 3 DB servers came back all the old connections didn't go to them & continued on Server1 i know that only new connections will go to them ( but at my case case here there will not be new connections because application server has one TCP connection with DB server serving all users ) , so How can i solve that & force re-load balancing ? The When CLIENT_ACCEPTED Irule will be applied only with 3 way Handshake ( new connections )