From looking further into the contents of this post, yes, that is technically possible, but likely has to be done as a DIY solution given it requires:
- the tablet itself to have the correct hardware
- following the standards of something called an "Accessory Charger
Adaptor" (ACA) which is not commonly available as something that can
be easily purchased. **.
**For example I found just one product that's the closest match to what I'm looking for.
Looking into the "BC1.2_without errata 2010-12-7" document of the "Battery Charging v1.2 Spec and Adopters Agreement", it tells us the ACA can have three ID resistances, one of which allows connection while charging ("RID_C" of somewhere between 36 and 37 k-ohms).
If that resistance is pulled up to the VBUS power line, and if there exists an ID comparator connected to the ID pin on the tablet side, then that would be one of the minimum requirements for it to work.