Merge Texture sets at export

Control over UDIM export would be awesome - being able to export by UDIM set and not texture sets.  I'm running into a use case where I have different texture/mat groups sharing a UDIM tile, and they're exporting as split textures.  This would also be useful so that an asset like a character that uses different mat groups (skin, clothes, etc) can just have one fbx being used for rendering and in painter, instead of needing separate fbxes for texturing and rendering. 

My Painter is updated to the newest version, but I haven't seen a solution to this issue "within" Painter  I'm very impressed with how Painter has advanced past the exploding models to avoid bake overlaps and has added individual control for choosing which HP models bake to the LP models, etc, even if it's within the texture sets.  This control is very powerful, yet not having the ability to combine these texture sets on export seems like an unfinished feature. 
Not sure if it would be helpful, maybe adding the ability to paint across texture sets could be the initial check for mixed UVs and if the textures are meant for a combined export.
Hopefully I haven't missed an already implemented solution, but please let me know if I have.

I wish I could upvote for every user of my plugin that clearly wants this feature (and then some for all the folks that can't afford it). I've sold hundreds of licenses over the last 6 years doing it through the JS and Python APIs. I can say it's a little complicated to solve for the issues outlined above (overlapping UVs, etc.) but well worth it to the users. I'd happily give up my revenue stream to have it built in. 

I don't agree that it's unnecessary. I have a model that has one UV map for all parts, but the model has several variants of itself, and I am not ok working with them, because they overlap each other, and if I split them into different texture sets, then when exporting I will have 4 textures instead of one.

This would be a welcome change and might even be simpler to implement than you think if approached the right way. If there are concerns about the user experience for new users, my counterpoint is to make it optional, so the experience remains unchanged for them. Additionally, providing documentation for this feature would ensure clarity for those who want to use it.

My rough initial vision of what I'd like to see is a system similar to selecting shaders for texture sets, but instead, it would involve selecting sets for UVs. Additionally, we could reference UV channel names for a quicker setup, making the process more efficient and streamlined.

This would be a huge feature for those like myself who create DAZ3D products, where you need to consolidate textures into one map.  

Would be a great feature to have! 

highly needed

Yep, it could be awesome !

We definitly need this!