How to properly format a regular expression in Java?

Question

Java

There is a line like "ping pong 123".
There is a regular expression:

Pattern p = Pattern.compile("ping\s*(pong\s*)?(?<SimpleText>.+)?");

Is it possible to somehow indicate to Java that if there is a word "pong" - then it should be in the first group, and not in the SimpleText group?
Those. I want to get results like this:

Matcher m = p.matcher("ping pong 123");
System.out.println(m.group("SimpleText")); // ожидается 123

Matcher m = p.matcher("ping 123");
System.out.println(m.group("SimpleText")); // ожидается 123

Matcher m = p.matcher("ping pong");
System.out.println(m.group("SimpleText")); // ожидается null;  по факту: "pong"

Those. I want the result to be null in the last example, not "pong".