How to separate NICS for SQL traffic, "Search" server traffic

This could we be a stupid question, but here it goes:

I will put together a Sharepoint solution.
It is recommended that I make a NIC available to handle SQL traffic, and
another NIC available connected to the respective "Sharepoint Search"
server.

Imagine I will place my Sharepoint servers in just one network segment,
let's say 10.0.0.0/8.

Since I have no way to segment this network further (imagine I have no
available routers to provide such layer 3 segmentation to separate the SQL
server from the "Search" server), do you see a supported way I could specify
Sharepoint_Server_NIC1 => Connects to my SQL Server only,
Sharepoint_Server_NIC2 ==> Connect to my "search" server ?


"Recommendation

Use at least a 100-MB network between servers in a server farm. Equip the
Web servers in a farm with two network cards-one for user requests and one
for SQL Server and search network traffic."