I haven't try this config in my css and really think it needs some modification. But, here is the idea how to make it work.
service server1
prot tcp
port 81
ip address 10.x.x.x
keepalive type tcp
act
service server2
prot tcp
port 82
ip address 10.x.x.x
keepalive type tcp
act
owner test
cont part1
prot tcp
port 80
url "*/part1"
add serv server1
vip addr 10.y.y.y
act
cont part2
prot tcp
port 80
url "*/part2"
add serv server2
vip addr 10.y.y.y
act