The ask makes little sense to me.
The groom is physically simulated.
To export that data you would have to “record” the actual performance.
I’m about 90% sure you cannot do that in unreal for the groom at the individual strand level.
It would be an insane amount of data to juggle. Possibly outside the capabilities of modern day computing when it comes to write speeds required at every frame.
I may be wrong - and if so that’s actually an amazing engine feature.
However to move the data to somewhere else, that somewhere else would need to know how to interpret that data.
Rendering engines usually have their own physics - so the simulations would all be different with different formats on an individual DCC basis…
Maybe, you could try and get the groom system to actually record into an alembic geometry cache - but again, the amount of data required can be insane, depending on strand count…
If this isn’t what you meant or how you need it - Mayne we need a better explanation of the issue.
If you just need the groom exported with the material - for instance - without the data, you may need to go back to the original model.
Most things are one way into the engine. Even FBX doesn’t export back out the same way it came in…