Muting text sounds when already on the text screen?

[Windows Central Question]

I have a Nokia Lumia 635 running 8.1, and whenever I get a text with my phone in my pocket or whereever, the normal ringtone plays which is fine, but if I'm already on the texting screen with someone and I get a text from them, it plays a different and more annoying tone.

Is there a way to disable just the tone when I'm already texting? I really see no point in having a sound play when I can clearly see if I got a new text since I'm already on the screen.