Any way to select multiple groups?

[GroggyKong]

So basically in all the original versions of AoE as far as I remember, and the vast majority of strategy games, selecting control group 1, then pressing shift-2 would select both control groups 1 and 2, as opposed to merging them. This made moving big armies easier to do in one go, and then made it easy to split them up when they got to their destination. Now I have to reform the different control groups, or make sure when using the drag select that only the units I need to be selected, are.
Is there any way to change the selection options?

[idiotdoomspiral]

The problem is AOE3 only allows you to select a maximum of 50 units. It would be great if DE allowed more, it's not like modern systems couldn't handle it but perhaps it would exacerbate the already janky pathfinding.

Multiple groups would probably go over that 50 unit mark easily, which could be complicated to design mechanics for.