Best solution for physical exchange place

Hi, I am goin to open a store where I will buy/sell multiple cryptocurrencies for cash and I am looking for some suitable solution which supports multiple cryptocurrencies and is easy to use. My idea is that a customer will come and sell me, for example, Ether for cash - I will give him cash and he will send me Ether which I would like to sell immediatelly into Euros. Also, if the software would count % of commission that would be even better.
I’m looking for something like this, except it should support multiple currencies:

Anyone could give me any advice?
Thank you! :wink:

Well, in Bisq every trading pair has base currency at one end (Bitcoin or Litecoin can be set as base currencies).

API is not fully developed yet for Bisq, I think, so you would have to do trades manually in Bisq.