In the GMT game, Space Empires, when you build ships you represent them with a group counter and a token indicating the number of ships in that group. Both these tokens are hidden information until you engage an enemy in combat.
When moving, an entire group moves together. My question is can the group be split into multiple groups with their own tokens in later turns? If so, can it happen during combat (for the purposes of screening) or only during the movement phase?
Space Empires has the most up to date rules on their website:
Space Empires Rules
Section 2.3 Groups says:
Groups are merely a way to represent a group of ships of the same type and technology level. Ships of the same type and technology may join and leave groups as they choose at any time (as counters allow).
Section 4.0 Movement says:
Movement is voluntary, and a player may move one, some, or all of his groups or none at all, in the same Movement Phase. Units may be moved separately or together.
Section 5.0 core combat section doesn't explicitly say you may split your ship groupings but in the rules of retreat you may split your groups.
Section 5.9 Retreats:
Retreat may require a player to place a new Group counter on the game board (that is, if one ship in a group retreats leaving the rest of the group in the hex)
With all the above rules in mind, I would think that you would be able to group or split your ship groups as needed during combat, movement, or retreats during your turn.
