JVB Load balancing Type (By Conferences or By users )?

Hello , Could you tell me the below issue,

user1 , user2 , user3 , user4 in conference A
user5 , user6 , user7, user8 in conference B
jvb1 installed with All other services. and jvb2 installed on a seprated machine.

so how the load balancing working. Type1 or Type2 ?
Type 1, Load balancing For conference. Such as:
Conference A (include User 1,2,3,4) in JVB1, and conference B (include User 5,6,7,8) in JVB2.

Type 2.Load balancing For User. Such as:
Conference A (include user1,user3) in Jvb1 and (user2, user4) in JVB2
Conference B (include user5,user7) in Jvb1 and (user6, user8) in JVB2