I am presuming DoE groups ( but my answer will cover most options)
Where possible, dont cook in a porch (your risk assessment will probably indicate this is a no no, you need to bear in mind that the kids arent as experienced, have less of an appreciation of the hazards involved and will be more impulsive than you are).
The camps sites I choose for groups usually have an undercover area (similar to an open sided barn) where the kids and the stoves can be out of the rain. This negates this issue, allows the kids to dry off a bit, and helps to keep their tent inners a bit drier and cleaner. Even where there isnt an offical cooking barn, I can usually negotiate use of somewhere suitable (roof, garage type large door)
I also have a tarpaulin (which doubles as a gear trailer cover) and some poles/rope/pegs so I/we can throw up a kitchen shelter if needed.
If...and only if...cooking in a porch is unavoidable I use a trangia over any other stove - they are very stable and the flame is fully enclosed. A gas trangia is even better. What I have got the kids to do is designate one tent as the cooking tent - they then take it in turns. its easier to control.