You should be good to set src-address in your dst-nat rules matching the subnet of your specific vlan.
If you have more address spaces to cover, you might be better off with an address list.
And I think your post is better placed in General.
MTCNA, MTCUME, MTCWE
There are 10 types of people: Those who understand binary and those who don't.
There are two types of people: Those who can extrapolate from incomplete data