As the resident Ariadna player, I've had to come to terms with Combat Groups pretty early on. I figured I should present an article based on my experiences...
Orders provide for a limited resource within Infinity, and the key to winning in Infinity is properly managing that limited resource. This is pretty self-evident to any Infinity player, but this is what leads to the problem with combat groups, which impose a strict segregation of orders to use. Many a time have I cursed myself for having an abundance of orders in one combat group and simply not enough in the other. Therefore, here are some guidelines to consider when creating combat groups:
1. If you have multiple combat groups, don’t have any that generate less than seven orders. It’s tempting to have a combat group of 10 and then just put the remainder into a second group, but you’re effectively wasting points at that point with guys that don’t have enough orders to be flexible to the demands of the table. If you end up having 11-13 orders in your entire army, try reformulating the list, because that is not a good area to be in.
2. Have Regular Troops outnumber Irregular Troops in every Combat Group. Again, you need that flexibility to use your irregular troops more than once if necessary. When I play Caledonia, I stick my Galwegians (irregular and dogged) in the same group as my Volunteers (regular and linkable), because I need to have those extra orders on hand in case one of them takes a wound, gets close to someone in camouflage, etc. Nothing hurts worse than having your irregulars only get one order per turn, simply because you don’t have enough orders to go around.
3. Keep in mind that you can only coordinate actions within combat groups. This is something to consider when evading ARO and not doing shooting based attacks (such as getting your melee troops up the field). I don’t tend to use coordinated actions too often, but when I do, it has saved my bacon. My particular favorite is charging my Galwegians through an open field. “Oh no! The burst on their chain rifle gets halved! Oh wait…” Granted, my brother has done the same thing to me with his Naffatun, so take your pick.
This list is far from exhaustive, but these are things to consider when building a list. Again, I stress that these are guidelines. I only mention these above because I have fallen into each and every one of these traps before.