Annoying group formation... bug?

Ok... this is something that really ticks me off.

Sometimes unselected units consider themselves to belong to another unit group and do what they do, for no understandable reason...
For example, I'm playing with a roman army that looks like this:

GROUP I
2 cavalry units
GROUP II
2 cavalry units
GROUP III
4 infantry units
GROUP IV
4 infantry units
GROUP V
4 skirmishers

Some time into the battle I decide to split up group III into two smaller groups (one remaining group III and the other one becoming group VI). Done. Then I decide to move group VI to engage the enemy. They charge... but what else? My 4 skirmishers have now decided that they belong to group VI as well, and they charge... nice... then they die.
The skirmishers where never selected when I issued the charge order nor do they actually belong to group VI... (I desperatly try to regroup (re-creating the groups) and after a few attempts it works. But then the cavalry gruop II think they belong to group VI... damn, now they die too.)
Similar problems happen to me all the time...

Back to my point... if anyone could understand my problem and above example then I have a question. Has anyone else experienced this and is it possible to prevent it in any way?

Same problem here. Sometime even formations that have never been together, were not the same kind of unit and were not highlighted followed the orders of other units. Once my artillery group chased routers just because my cav. group had been given the order to pursue. whenever I stoped the horsies, the stupid ballistas stoped too. Had to return each unit to position individually. :whip:

Yes this does happen. What you must do is remove the skirmishers from the group that they remain in in after you take out the Inf.

So, select the skirms and hit 'group' key twice, to delete then reform unit.

Its wierd, stuff in RTW can be controlled several ways...at the same time. This is especially cumbersome when remapping hotkeys. A good and bad thing, just gotta be aware of it.