We have a ATM Network and we want to sell and buy BTC or ETH on our ATMs, using our own switch. How can we do it?
Unless I'm misunderstanding you. You just need to track the multi-currency balances inside your own gateway. There are a number of ways you could do this but without more information its difficult to help. We recently built a Ripple based solution which keeps track fiat and virtual deposits using Ripple and you might be able to build or purchase something similar. I hope this helps.