in ROTJ we see Scouts working in 2-man teams in a number of instances so that's my reasoning for that with the Scout, Brent... They were always in groups of 2 on Endor save for the 4-man group at the bunker.
Ryan gave a good synopsis of "teams" and such though...
In STar Wars though, there's possible room for play there too... The term "Legion" comes up of course as a large grouping of soldiers... There's some info on this stuff, mostly formed in minis/RPG gaming I'd say. Any size grouping could vary by the types of soldiers and things...
In Republic Commando a team is 4 men... Each a specialist in a specific field save for the Commander who is sort of the all around expert. They each can act as effectively independantly though as they can as a team really. That's one example of how SW hashes out soldier groupings though, at least in the EU...
In the films the only positive I can think of is the Scouts off-hand... Stormtroopers aboard the Tantive IV seemed to be fanning out in teams of 3 IIRC, as that's the # that stumbled upon Leia and lost a man to her shot... I know there's clusters of troops marching together throughout ANH but I can't recall sizes offhand.

My nerdyness only goes so far I guess.