Training with one TOC employed by another

[Zuko]

I've read somewhere on here that some TOCs send their trainees to other TOC to be trained up, I assume it's because they are under the same company as a whole (GTR).

What I want to know is, is it possible for this to happen if you are in two talent pools ie Southeastern and Thameslink?

 

[bionic]

I know Southeastern trained some Thameslink drivers up a little while back but I've since heard Thameslink are now 120+ drivers surplus so have frozen all driver recruitment and won't be taking on, or training up, any new drivers for the foreseeable future.