dnsmasq, manage different subnets ?

Hello all,

I'll have to manage (dhcp) a specific vlan of our school. This vlan is multi-site (3) managed by cisco routers (same lan). Every site has it's own subnet. I need to configure my dchp to a attrib different IP adresses according to the vlan the request comes from. It seems (I'mw waiting for the confirmation of that) that the routers have the dhcp-helper activated to route the dhcp requests to my dhcp server. Is
If enter the dhcp-option=eth1,xxx and all parameters for my different subnets, will it be enought to deliver different ip addresses on each subnet ?

2. It seems that dnsmasq is made for small networks ,, so would it be possible to replace dnsmas with another dhcp system ( isc-dhcp for example) ?
thanks to all