One port, Multiple VLANS, catalyst 3750G

I've been doing some searches and I don't know if I missed any, but I need some aid.

I have one common link for three networks each being on the same vlan

1. They are connected like this A link 2950 catalyst B link 2950 catalyst

both plug into a switch(no configs that matter in this scenario) that just sends one C link to a 3750 G switch.

They need to access Network D which sits on the other side of an ASA.

My situation is now I want to assign different subnets for the networks behind links one and two and let them use my ASA as their gateway.

So A link, VLAN 30 10.0.0.0/24 B Link, VLAN 40 10.1.1.0/24 D Link VLAN 20 10.1.3.0/24 E int VLAN 10 10.1.2.0/24

So this is what I've come up with thus far.

Configure C link port to accept multiple vlans Configure ASA interface E with subinterfaces for gateways for each subnet

So in theory I think this is how it should be, can anyone confirm and if so, can u tell me how to configure the multiple vlans on the Clink port?

Much Appreciation