How to add sectional variable header in gtsummary tbl_summary

Question

I have a current table creating using the following code:

table1 <- 
  ptbl %>%
  dplyr::select( pt_gender.factor, pt_race.factor, pt_ethnicity.factor, education.factor, employed.factor,marital.factor,
                 home_smoker.factor,quit_support.factor,past7.factor) %>%
  tbl_summary(
    label = list(pt_gender.factor ~ "Gender",
                 pt_race.factor ~ "Race",
                 pt_ethnicity.factor ~ "Ethnicity",
                 education.factor ~ "Education",
                 employed.factor ~ "Employed",
                 marital.factor ~ "Marital Status",
                 home_smoker.factor ~ "Live with smoker",
                 quit_support.factor ~ "People around are very supportive of quitting smoking",
                 past7.factor ~ "In the past 7 days, did you smoke a cigarette (even a puff)?")) 

I am trying to add two sectional titles to my table, one is "Demographics", and the other one is "Smoking Habit".

I want my table like

Demographics Gender .... Race ... Ethnicity ... ...

Smoking Habit Live with smoker ... People around are very supportive of quitting smoking .....

Is there a function to do it?