Normally, I don't try to explore much that early because it's too costly.
Indeed, sometimes, I would like to see modders trying to merge each other works.
Walter Walkwood and his crew from Realism Invictus could benefit a lot from PAE mechanics while the inverse is also pretty much true.
What you refer is "Stack Aids" promos from RI. When attacking with other units tagging along, the unit will get several modifiers depending the type of unit.
Of course, there is none in PAE.
Come to think, if I ever started a RI PBEM, I'm sure Tigranes would choose Armenia right off the bat. I bet 100$ on that.