How do I separate some of my troops into another control group effectively in Starcraft 2?

There is this situation, where I would like to separate some of my troops at a location, and pull the rest of the main group somewhere else. The larger group should stay assigned to the current control group, whereas the new guys (2 to 5) will get assigned to another group, to access them later.

These two groups are to be stationed far from each other.

How do I do this efficiently?

I have tried picking a couple of units from the back of my crowd and assigning them to another group by Ctrl+2, but I don't know how to regroup the larger crowd into control-group 1 again. Boxing them is always difficult, since there is little distance to the new group.

Solution 1:

Usually I do the following:

1. Press '1' key to get my 'BIG' group (lets consider 30+ zerlings);
2. Send whole group to required location (attack or move to potential opponents expands);
3. Press Shift key and click on 1-2 units in group (this way you exclude few units from current selection, in current selection you will have almost whole original group excluding 1-2 recently clicked units);
4. Repeat steps 2-3 (send whole grope to new location and exclude more units from group) if you need to send different samll groups in different locations (useful to get map vision);
5. Do 'move back' command to group (units excluded from group earlier will go on their destination while all other units will remain currently selected and will actually keep on previous position);
6. Press Ctrl+1 (to rebind to the same group number all units except of 2 that were commanded to atack/move forward).

As a result, '1' still keep whole group, your group will be on almost the same place when it was in the begging, required units go into required destination point, these units are excluded from the main group. If you need to grad these units in another group - in 2-3 seconds you will be able to select them easily (as they will be separated from your main group).

Solution 2:

There's no quick way to do what you want (as in, automatically assign to a new group at the same time you move out of their current group). You have a few options if you want to avoid box-selecting (although I don't know why you would, it's quicker).

Method 1: Establish Small Group First

This will ensure you don't have to make a 'useless' move, but you click a lot more if you refuse to box-select.

• Hit escape to clear out your current selection.
• Shift-click (click while holding the shift key) each unit you want to add to your small group.
• Hit Ctrl+2 to save your new small group.
• Move them to their remote location.
• Hit escape to clear out your current selection.
• If you refuse to box-select the remaining units on the screen, shift-click each unit you want to put in the large group. You can see why a box-select would be much easier.
• Hit Ctrl+1 to save your new large group.

Method 2: Establish Large Group First

This involves a possible small movement of your large group, depending on your click accuracy.

• Hit 1 to select your large group.
• Shift-click each unit you want to move out of that group.
• Hit Ctrl+1 to save your new large group.
• (Optional) Move your main group away.
• Hit escape to clear out your current selection.
• Shift-click each unit you want to add to your small group.
• Hit Ctrl+2 to save your new small group.
• Move them to their remote location.