It seems you could use an environment or a function. Here is some simple code demonstrating how objects defined withing those are not available in the Global Environment.
E <- new.env()
E$a <- 3
E$b <- 2
a + b #Error!
E$a + E$b # returns 5
MyFunc <- function() {
x <- 5
y <- 7
x + y
}
x + y #Error!
MyFunc() #returns 12