When I have a big group of pets to train I put them in one tab to keep track of them and send out an inn request for a trainer. Then I go through the group one by one and click train on each pet.

What I think others and I will benifit from is, like the send all pets to arena, an option to send all pets to trainer, or riding hall, or other wording.

There should be a popup saying something like "Training will cost xxx silver. Do you want to continue?"

What do you think?

The problem with this idea is that the ridinghall has limited capacity, so if you have more pets in the group than rh capacity how is the game supposed to decide which pets to train.

^That. 

But it may be neat to have a group that you can add them to that has the max capacity for the ridinghall... I'm not sure if the outcome of this will be enough to advocate for the time spent coding, or if we can code it. But it could be quite interesting. 

I think what may be better would be to have pets 'permantly' in the riding hall until leveled to your structure's maximum. While it doesn't address wanting to send multiple pets, it does address having to re-send. Maybe there could be a slight discount. The time would still be the same (more or less). 

Oooh yes I love that idea nightingale! I could plop my group into the ridinghall and I wont constantly forget to go back every four hours to train them. I end up getting a trainer invite for three days, and training the group just twice because I keep getting busy and forgetting. Yes yes I would love to leave them in the ridinghall.

In the meantime it might help to use some sort of timer to remind you when the four hours are up. Using one I generally manage to train my pets 4-5 times a day depending on when I go to bed/wake up.