Rxjs do something on first emit from multiple subscriptions

Is there a clean way to do something on first emit from multiple subscriptions ?

e.g.:

this.subscription1 = this.service.getData1().subscribe(data => {
this.data1 = data;
console.log('1');
});

this.subscription2 = this.service.getData2().subscribe(data => {
this.data2 = data2;
console.log('2');
});

// Do something after first emit from subscription1 AND subscription2
doSomething();

...

doSomething() {
console.log('Hello world !');
}


Output goal:

1
2
Hello world !
1
2
1
1
2
1
2
2
...

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