Very simply you can open 4NT which asks partner if they hold an ace.

5♣No aces
5The ace of Diamonds
5The ace of Hearts
5♠The ace of spades
5NT2 aces
6♣The ace of clubs
6Three aces!?

Alternatively you can play a step response:-

5♣No aces
5The ace of Clubs
5The ace of Diamonds
5♠The ace of Hearts
5NTThe ace of spades
6♣Two aces
6Three Aces!?

Again the most important thing is make sure you agree what you are playing with partner…as the specific ace convention doesn’t arise very often I would suggest you play the first alternative described here.

Please make sure you can handle any response…if you hold:-

Now the opposition are bound to lead a red suit and take you one off in 6♠.

Whereas if you have this you can cater for any response:-