Hashurl policy priority is just higher than default policy. The requests on a VS, which contains hashurl policies, will be directed to one of the groups associated with the VS through hashurl policy.

E.g:
slb policy hashurl p1 v1 g1
slb policy hashurl p2 v1 g2
slb policy hashurl p3 v1 g3
slb policy hashurl p4 v1 g4
slb policy default v1 g5