Disable SMB sharing for specific NIC on server 2012

I have 2 servers running windows 2012 R2, one of them is SMB server and the other is iSCSI server, and the clients are using Win7 x64.

Now I want to separate networks between iSCSI and SMB using 2 NICs on client and server. In order to do this, I need to disable SMB on internal NIC of SMB server and leave the external NIC SMB feature enabled.

But I'm having trouble disabling SMB sharing for specific NIC on server 2012 R2

Unchecking file and printer sharing doesn't have any effect. Is there any other way to do this?

NB: I read about SMB Multichannel but, the problem is, my clients' spec doesn't seem to be compatible with Win10..Its very laggy compared to Win7

It's a bad idea to use dedicated cabling (+non-redundnant in your case!) for SMB and iSCSI traffic. It would be much better idea to chunk physical LANs with VLANs, configure QoS and give both SMB and iSCSI at least two VLANs: for performance and fault-tolerance.