Context:
I have a dataframe of individual people grouped by household, which includes relationship parameters for each individual describing their relationship to every other individual in the household.

Goal: I am trying to create sub-groups within households according to tax-units. Individuals are considered a single tax-unit if they are (1) a spouse or (2) a dependent child. A dependent child is defined as a child under 18 or a child who is under 23 and a student.

There may be a single tax-unit or multiple tax-units within a given household. Other married couples, or individuals in each household who are not dependent children, form separate tax-units.

Example Dataframe:

   household     name age student                r01         r02          r03               r04          r05
1          1     john  60       0               <NA>      spouse       parent            parent       parent
2          1     mary  56       0             spouse        <NA>       parent            parent       parent
3          1    fiona  25       0              child       child         <NA>           sibling      sibling
4          1      tim  20       1              child       child      sibling              <NA>      sibling
5          1     nora  16       0              child       child      sibling           sibling         <NA>
6          2 terrence  58       0               <NA>      spouse child-in-law step-child-in-law       parent
7          2  siobhan  57       0             spouse        <NA>        child        step-child       parent
8          2      jim  90       0      parent-in-law      parent         <NA>            spouse grand-parent
9          2    maire  87       0 step-parent-in-law step-parent       spouse              <NA>        other
10         2     eoin  21       1              child       child  grand-child             other         <NA>
11         3   ronald  50       0               <NA>        <NA>         <NA>              <NA>         <NA>

Code to reproduce:

df <- data.frame(household = c(rep(1,5), rep(2,5), 3),
           name = c("john", "mary", "fiona", "tim", "nora", "terrence", "siobhan", "jim", "maire", "eoin", "ronald"),
           age = c(60, 56, 25, 20, 16, 58, 57, 90, 87, 21, 50),
           student = c(0,0,0,1,0,0,0,0,0,1,0),
           r01 = c(NA, "spouse", rep("child",3), NA, "spouse", "parent-in-law", "step-parent-in-law", "child", NA),
           r02 = c("spouse", NA, rep("child", 3), "spouse", NA, "parent", "step-parent", "child", NA),
           r03 = c(rep("parent",2), NA, rep("sibling", 2), "child-in-law", "child", NA, "spouse", "grand-child", NA),
           r04 = c(rep("parent",2), "sibling", NA, "sibling", "step-child-in-law", "step-child", "spouse", NA, "other", NA),
           r05 = c(rep("parent", 2), rep("sibling",2), NA, rep("parent", 2), "grand-parent", "other", NA, NA))

Approach:
To start I created variables to list family member order, and to identify a dependent child.

df <- df %>%
  group_by(household) %>%
  mutate(fam_mem = row_number(),
         dep_child = ifelse(age < 18 | (age < 23 & student == 1), 1, 0))

My next step was to then identify parents of dependent children, using match however this is where I am getting stuck, as match will tell me if they are a parent, but I cannot link it to dependence status.

After this I hoped sort by dependence status and use lag to create a new household variable name, which groups into tax-units, e.g. 1a, 2a, 2b, 3a.