Should the following scenario work?
I have a DHCP server on VLAN 101, with the IP 192.168.0.5. I have two other VLANs 102 and 103 where I want to hand out IPs the same range 10.20.30.40-240, but from different scopes. So a client on VLAN 102 could get 10.20.30.40 and a different client on vlan 103 could also get 10.20.30.40.
Their routing doesn't overlap, so there is no layer 3 issue.
I will configure the DHCP IP helper setting on the firewalls for each VLAN to forward the DHCP traffic to my DHCP server on VLAN 101.
I know the MAC addresses of all the clients in VLAN 102 and 103, so I can use a filter or static mapping to assign clients to the VLAN 102 scope or the VLAN 103 scope.