diff --git a/mxq_group.h b/mxq_group.h
index 3e2ff59..8ab438d 100644
--- a/mxq_group.h
+++ b/mxq_group.h
@@ -59,6 +59,9 @@ struct mxq_group {
 
 #define MXQ_GROUP_FLAG_CLOSED (1<<0)
 
+#define MXQ_GROUP_FLAG_HAS_DEPENDENCY (1<<1)
+#define MXQ_GROUP_FLAG_IS_DEPENDENCY  (1<<2)
+
 void mxq_group_free_content(struct mxq_group *g);
 
 inline uint64_t mxq_group_jobs_done(struct mxq_group *g);
diff --git a/mxqadmin.c b/mxqadmin.c
index 5b7d3de..55d64bc 100644
--- a/mxqadmin.c
+++ b/mxqadmin.c
@@ -118,8 +118,10 @@ static int update_group_flags_reopen(struct mx_mysql *mysql, uint64_t group_id,
     struct mx_mysql_stmt *stmt = NULL;
     unsigned long long num_rows = 0;
     int res;
+    uint64_t flagsnottobeset;
     uint64_t newflags = 0;
 
+    flagsnottobeset = MXQ_GROUP_FLAG_IS_DEPENDENCY;
     newflags |= MXQ_GROUP_FLAG_CLOSED;
 
     stmt = mx_mysql_statement_prepare(mysql,
@@ -127,6 +129,7 @@ static int update_group_flags_reopen(struct mx_mysql *mysql, uint64_t group_id,
                 " group_flags = group_flags & ~(?)"
                 " WHERE group_id = ?"
                 " AND user_uid = ?"
+                " AND group_flags & ? = 0"
             );
     if (!stmt) {
         mx_log_err("mx_mysql_statement_prepare(): %m");
@@ -136,6 +139,7 @@ static int update_group_flags_reopen(struct mx_mysql *mysql, uint64_t group_id,
     res  = mx_mysql_statement_param_bind(stmt, 0, uint64, &(newflags));
     res += mx_mysql_statement_param_bind(stmt, 1, uint64, &(group_id));
     res += mx_mysql_statement_param_bind(stmt, 2, uint32, &(user_uid));
+    res += mx_mysql_statement_param_bind(stmt, 3, uint64, &(flagsnottobeset));
     assert(res == 0);
 
     res = mx_mysql_statement_execute(stmt, &num_rows);
diff --git a/mysql/alter_tables_0.13.0.sql b/mysql/alter_tables_0.13.0.sql
new file mode 100644
index 0000000..b2046be
--- /dev/null
+++ b/mysql/alter_tables_0.13.0.sql
@@ -0,0 +1,5 @@
+ALTER TABLE mxq_group
+    ADD COLUMN (
+        depends_on_group    INT8 UNSIGNED NULL DEFAULT NULL,
+        dependency_of_group INT8 UNSIGNED NULL DEFAULT NULL
+    );
diff --git a/mysql/create_tables.sql b/mysql/create_tables.sql
index d134ab5..30365ce 100644
--- a/mysql/create_tables.sql
+++ b/mysql/create_tables.sql
@@ -53,6 +53,9 @@ CREATE TABLE IF NOT EXISTS mxq_group (
    stats_total_real_sec_finished    INT8 UNSIGNED NOT NULL DEFAULT 0,
    stats_total_wait_sec_finished    INT8 UNSIGNED NOT NULL DEFAULT 0,
 
+   depends_on_group     INT8 UNSIGNED NULL DEFAULT NULL,
+   dependency_of_group  INT8 UNSIGNED NULL DEFAULT NULL,
+
    INDEX(group_id),
    INDEX(group_name)
 );