diff --git a/R/join_data_tibbles.R b/R/join_data_tibbles.R
index e09a4d41..591e4465 100644
--- a/R/join_data_tibbles.R
+++ b/R/join_data_tibbles.R
@@ -11,27 +11,35 @@ join_data_tibbles <- function(suprtbl,
   suprtbl <- suprtbl |>
     mutate(pks = purrr::map_chr(.data$redcap_data, ~ extract_keys(., record_id_field = record_id_field))) %>%
     select(.data$redcap_form_name, .data$redcap_form_label, .data$redcap_data,
-           .data$redcap_metadata, .data$structure, .data$pks)
+           .data$redcap_metadata, .data$structure, .data$pks, .data$redcap_events)
 
   tbl_x <- extract_tibble(suprtbl, x)
-  tbl_x_type <- get_structure(suprtbl, x)
+  tbl_x_structure <- get_structure(suprtbl, x)
   tbl_y <- extract_tibble(suprtbl, y)
-  tbl_y_type <- get_structure(suprtbl, y)
+  tbl_y_structure <- get_structure(suprtbl, y)
 
   # Mixed structure requires special handling
-  is_mixed <- any(c(tbl_x_type, tbl_y_type) == "mixed")
+  is_mixed <- any(c(tbl_x_structure, tbl_y_structure) == "mixed")
 
   if (is_mixed) {
-    required_columns <- c("redcap_event_instance", "redcap_form_instance")
-    tbl_x <- add_missing_columns(tbl_x, required_columns)
-    tbl_y <- add_missing_columns(tbl_y, required_columns)
+    # TODO: Determine if ok to remove
+    # required_columns <- c("redcap_event_instance", "redcap_form_instance") # nolint: commented_code_linter
+    # tbl_x <- add_missing_columns(tbl_x, required_columns) # nolint: commented_code_linter
+    # tbl_y <- add_missing_columns(tbl_y, required_columns) # nolint: commented_code_linter
+
+    tbl_x_type <- get_type(suprtbl, x)
+    tbl_y_type <- get_type(suprtbl, y)
+
+    tbl_x <- left_join(tbl_x, tbl_x_type, by = "redcap_event")
+    tbl_y <- left_join(tbl_y, tbl_y_type, by = "redcap_event")
   }
 
   join_fn <- get_join_fn(type)
   by <- build_by(suprtbl, x, y, is_mixed)
 
-  join_fn(tbl_x, tbl_y, by = by, suffix = suffix) %>%
-    relocate(starts_with("form_status_complete"), .after = everything())
+  join_tbls(tbl_x, tbl_y, join_fn, by, suffix, is_mixed) %>%
+    relocate(starts_with("form_status_complete"), .after = everything()) %>%
+    select(-starts_with(".repeat_type"))
 }
 
 extract_keys <- function(suprtbl, record_id_field) {
@@ -50,6 +58,16 @@ get_structure <- function(suprtbl, tbl_name) {
   suprtbl$structure[suprtbl$redcap_form_name == tbl_name]
 }
 
+get_type <- function(suprtbl, tbl_name) {
+  suprtbl %>%
+    filter(.data$redcap_form_name == tbl_name) %>%
+    pull(.data$redcap_events) %>%
+    pluck(1) %>%
+    select(.data$redcap_event,
+           ".repeat_type" = .data$repeat_type) %>%
+    unique()
+}
+
 get_join_fn <- function(type) {
   join_functions <- list(
     left = dplyr::left_join,
@@ -84,8 +102,55 @@ build_by <- function(suprtbl, x, y, is_mixed) {
   out
 }
 
+# TODO: Determine if ok to remove
 add_missing_columns <- function(tbl, columns) {
   missing_cols <- setdiff(columns, names(tbl))
   tbl[missing_cols] <- NA
   return(tbl)
 }
+
+join_tbls <- function(x, y, join_fn, by, suffix, is_mixed) {
+  if (is_mixed) {
+    # Filter based on .repeat_type
+    x_together <- x %>% filter(.data$.repeat_type == "repeat_together")
+    y_together <- y %>% filter(.data$.repeat_type == "repeat_together")
+
+    x_separate <- x %>% filter(.data$.repeat_type == "repeat_separate")
+    y_separate <- y %>% filter(.data$.repeat_type == "repeat_separate")
+
+    # Join together sets
+    joined_together <- x_together %>%
+      join_fn(y_together, by = by[by != "redcap_form_instance"], suffix = suffix)
+
+    # Join separate sets
+    joined_separate <- x_separate %>%
+      join_fn(y_separate, by = by[by != "redcap_form_instance"], suffix = suffix)
+
+    # Bind rows together
+    result <- bind_rows(joined_together, joined_separate) %>%
+      drop_non_suffix_columns()
+  } else {
+    result <- join_fn(x, y, by = by, suffix = suffix)
+  }
+
+  result
+}
+
+drop_non_suffix_columns <- function(data) {
+  # Extract column names that contain a "."
+  # Note: We can look for periods because REDCap will not allow variables to made
+  # with them. Only user tampering with column names in the output would result in this.
+  dot_columns <- names(data)[grepl("\\.", names(data))]
+
+  # Extract the base column names without the suffixes (everything before the ".")
+  base_columns <- unique(sub("\\..*", "", dot_columns))
+
+  # Filter out base columns that do not exist without a suffix
+  columns_to_drop <- base_columns[base_columns %in% names(data)]
+
+  # Drop only those base columns that exist both with and without suffixes
+  data <- data %>%
+    select(-all_of(columns_to_drop))
+
+  return(data)
+}