I've one internet connection and I need to share it among two separate "identities" via some wireless connections. I have tought a solution like this:
one internet router (internal IP 10.0.0.1) one LAN router with 3 interfaces, one connected to the internet router the other two connected to two access point that provide two different networks to the two "identities".
As you describe it, most likely won't work. There is a hidden "gotcha".
As I understand it you will have:
1) Internet connects to WAN port of the internet router. That's OK.
2) LAN port of internet router connects to one of the LAN ports of the LAN router. That's OK.
3) LAN router LAN port1 connects to the internet router as in step 2) above. That's OK.
4) LAN router LAN port2 connects to the first AP. That's OK.
5) LAN router LAN port3 connects to the second AP. That's a problem.
Here's why. Connect only one AP to the LAN router and ping to x.x.x.255 or use a IP finder utility such as
find all the IP adresses ont the network. You see a .255 address.
What is happening is the AP generates a a .255 address. When you connect the second AP, it also creates a second .255 address. You'll get a IP address conflict and can't get into the second AP.
The solution is to connect the LAN router port2 to a switch and connect the APs to second and third ports of the switch.
Do you have line-of-sight between the buildings? If not, then stop, it won't work. Certainly not reliably.
If you do have line-of-sight (and it stays that way year-round, as in no leaves) then you can setup a point to point connection. There are any number of ways to do it. But basically you put two wireless routers with antennas pointed at each other. Then you set up the one in the second building to act as a 'client' of the first one. There are various network routing issues to consider but they're relatively straightforward to overcome. If you want laptop wifi coverage in the buildings you will need other access points for that. The ones between buildings do that, and only that.
But then you have to balance the hassles of doing this, AND keeping it running, against just getting a second internet connection.