Better way to write if statement with a lot of ||

I wonder if there is a more elegant way to write an if statement with a lot of || in java.
I've given different values to alphabet letters:
A,O,I,B,T,S,M,N -> 1 
C,D,F,G-> 5 
W,Y,Z,H,Q       -> 10

So, I want to check a given letter and if is equal with one of  the 2nd group for example to get 5.
Right now I'm checking like this:
String value;
if (getLetter().equals("Α")|| getLetter().equals("O") ||
    getLetter().equals("I") || getLetter().equals("B") ||
    getLetter().equals("T") || getLetter().equals("S") ||
    getLetter().equals("N") || getLetter().equals("N"))
value = "1";

is there a better way to do it?

Three options:

Use a switch statement, assuming you're using Java 7 or 8:
switch (getLetter()) {
    case "A":
    case "O":
    case "I":
    case "B":
    ...
value = "1";
    ...
}

Use three Set<String> objects
(Best, IMO) Use a Map<String, String>

The last option would be something like:
// You'd presumably initialize this in one place...
Map<String, String> map = new HashMap();
map.put("A", "1");
map.put("O", "1");
map.put("I", "1");
...
map.put("C", "5");
map.put("D", "5");
...

String value = map.get(getLetter());

String letter = getLetter();
if ("AOIBTSMN".contains(letter)) 
    value = "1"; 
else if ("CDFG".contains(letter))
    value = "5";
else if ("WYZHQ".contains(letter))
    value = "10";

Not optimal, but short, clear and self-explaining.