How do I manipulate morph targets within an animation blueprint

Hi Guys,

I have a stylized character with ARKit morph targets to do facial capture via live link.
I had the problem that the app would track small bits of morph targets even if I was doing something else.
For example I was smiling but the app was tracking a little bit of mouthFrown which added uggly curves to the mouth.
I would like to manipulate the morph targets within an animation blueprint so that for example I could deactivate mouthFrown or other morph targets when the value for mouthSmile goes above 0.5 or something like that.
Sadly I can not get it to work, also in combination with the live link pose node which I need.
I hope someone can help me with this xD
Would appreciate it a lot.