Just started playing again after having the game for a couple of years. Even though I had played earlier versions of Civ this one just didn't click the first time(I was probably going through a WOW phase

).
I've combed this website and haven't been able to figure these nuances out.
1. Strategic Resources (supply lines)....
A. If I have an Iron Resource attached via a road/Mine to City A, can City B use that resource if theres no connection via road, river, or coastal?
B. If I have access to only 1 Alum. resource in my Empire and have it attached to City X and City X is making something that receives a production bonus (like cutting prod. time in half) from Alum, and If I'm building another item in City Y that also receives a production bonus from Alum can City Y also take advantage or is that 1 Alum. resource considered "tied up" with the production of the 1st item?
This comes up because last game I was building 2 parts of the Spaceship and only 1 city got the resource bonus even though all my cities were connected by rail.