Looking at the Space marine Codex the Rule states "The decision to split a unit into combat squads, as well as which models go into each squad, must be made when the unit is deployed. Both combat squads can be deployed in separate locations." The exception being a drop pod.
So reading that rule one can safely assume that you can deep strike terminators or assault marines in combat squads into two separate locations, right? Well maybe yes and maybe no, it depends on what deployment is. The term deployment is not clearly defined in the rule book that I have found, and by my interpretation of the term it falls into one of two meanings.
Meaning A: A unit is deployed when it comes into play, but has not been placed on the table.
Meaning B: A unit is deployed when it comes into play and is placed on the table.
Looking at these if we use Meaning A as the definition for Deployment then a unit can combat squad and still deep strike into two separate locations. Using Meaning B as a reference then we essentially use the rules for drop pods. The unit deep strikes as one unit and splits into combat squads after determining the deep strike location.
As a marine player I am personally fond of Meaning A for deployment, as it allows combat squads to deep strike into separate locations and allows the Marine player more flexibility.
The alternative is to simply define combat squads at the start of the game, make use of the "Treated as separate units" rule and deep strike them individually.