It is indeed possible. You’ll want to comment out the line activating the initial activation of the user move state in the subsymbol and then call that in your main parent symbol.
I’ve created a quick example with a modified world tracking subsymbol:
World Tracking 3D Model Tap to Start Example.zpp (13.7 MB)
You’ll notice that I have a script node under the button in the Hierarchy. As the world tracking subsymbol is modified, all you need to do is call:
I’m then also hiding the button group when tapped (using a controller + state), so it’s not overlaying the screen.
Please note, this method won’t work using the standard world tracking subsymbol found in Studio. If you want to use this method, you can use the subsymbol here:
World Tracking Ground Placement - modifed.zpp (1.1 MB)
Hope this helps.