I think the answer to this one will be "no", but just in case...
There seem to be things you cannot do to lines within groups or between groups.
One of the annoying ones is the fact you can't seem to be able to split lines if they are grouped together (or indeed split an ugrouped line against a line that's in a group).
I don't see any logic in having this restriction so I'm wondering if I've missed something obvious? A function override key perhaps?
