In general, suggestions can be made using the glTF-Blender-IO Issue Tracker, which tracks feature requests as well as bugs.
You might be surprised to find that this, or some variation of something similar to this, might already work, although it's been deprecated for quite some time.
So for a bit of history here, before the current glTF-Blender-IO project came to be, there was a predecessor project called glTF-Blender-Exporter that used a Blender 2.79 node group called "glTF Metallic Roughness" that looked like this:
An obsolete .blend project with this grouping is still available from the archived GitHub project. It's similar to the node you've shown above, except the Principled BSDF node is included inside the group.
This node grouping proved too cumbersome for many users to learn, and it was eventually abandoned in favor of using the Principled node directly. But last I checked (and it's been a while), there's still some legacy code in the exporter that supports some portion of this for the sake of backwards-compatibility. That code was extended to support the Occlusion map (on glTF Settings), because Occlusion is the only setting here that isn't available anywhere else that the glTF exporter can find.
So if you bring the Principled BSDF inside your group node, and use some of the names listed here, you might be able to find inputs that still work. One thing to be careful of: the ones named "Factor" only accept un-connected colors, and the non-factors only accept textures. Also, newer glTF properties such as ClearCoat and Transmission were only ever connected to Prinicpled BSDF, not the obsolete group node. The other thing to be aware of is that this system of material design historically produces strong opinions in users; some have publicly lamented its passing, while many others cheered its demise.