This is a good idea, but it's an optional thing and many will just ignore it. Just msg them ingame or go to their alliance discord and ask for the right person.
If you find it har to manage your cities then don't buy more, problem fixed.
What could be usefull would be to bulk buy infra for more cities then just one at the time.
This is good, the one thing i would add would be 30-40k mun to buy it, just bc we have less alu, steel and gas than mun ingame.
Cost:
Cash: $20,000,000
Uranium: 5,000
Gasoline: 10,000
Steel: 20,000
Aluminum: 20,000
Munitions: 30,000/40,000