Lookup shortcuts for routes going out the same interface?

Hello,

I am trying to run some tests on packet forwarding (IPv6) in a network 
of containers. I'm using a lot of source address constrained routes, 
inserted as:

ip -6 route add <dst_addr> from <src_addr> dev <interface>

There will be much less interfaces than routing entries, and I wanted to 
know how the lookup works.

If I have 1000 routes all going out of the same interface, will the 
lookup take some shortcut and automatically forward a packet toward that 
interface? Or will it act the same way it would if each of the 1000 
routes had a different outgoing interface?

Thank you.