I have two buildings that are next to each other. We have an HP switch
in each that is connected by fiber.

I currently have 1 DHCP server in Building A and it services both
buildings. Currently I have users that travel between the buildings. In
order to make things more efficient, I am trying to have Building A use
one subnet and Building B use another. I have 2 subnet ranges.

I would like building A to use one for example 192.168.10.x and building
B to use 192.168.20.x. How can I go about doing this? Every time I
create network ranges both buildings always start using one range. I am
not sure what is determines what range it uses though.

I thought I could setup a VLAN in building A called VLAN_BA and a VLAN
in Building B called VLAN_BB. Then setup two DHCP pools. VLAN_BA and
VLAN_BB. Doesn't work.

I assigned building A network range to VLAN_BA pool and building B
network range to VLAN_BB range. Doesn't work. What do I need to do
further to make this happen? Or can it be done?