If I understand your question correctly, what you are looking for is a method to subset your data.frame, based on a binary variable. Luckily, base R has a function for this called subset. Here is an example using the built in dataset mtcars.
> head(mtcars)
mpg cyl disp hp drat wt qsec vs am gear carb
Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
model_1 <- lm(mpg ~ cyl + disp + hp,
data = subset(mtcars, vs == 1))
model_2 <- lm(mpg ~ cyl + disp + hp,
data = subset(mtcars, vs == 0))
Hope this helps!