diff --git a/sysusers.prov b/sysusers.prov
index a6eda5d..f12e929 100755
--- a/sysusers.prov
+++ b/sysusers.prov
@@ -1,5 +1,40 @@
 #!/bin/bash
 
+process_u() {
+    if [ ! -z "${2##*[!0-9]*}" ]; then
+        # Single shared static ID.
+        echo "user($1) = $2"
+        echo "group($1) = $2"
+    elif [[ $2 == *:* ]]; then
+        # UID:<group>.
+        uid=$(echo $2 | cut -d':' -f1 -)
+        group=$(echo $2 | cut -d':' -f2 -)
+        if [ ! -z "${group##*[!0-9]*}" ]; then
+            # UID:GID.
+            echo "user($1) = ${uid}"
+            echo "group($1) = ${group}"
+        else
+            # UID:<groupname>.
+            echo "user($1) = ${uid}"
+            echo "group(${group})"
+        fi
+    else
+        # Dynamic (or something else uninteresting).
+        echo "user($1)"
+        echo "group($1)"
+    fi
+}
+
+process_g() {
+    if [ ! -z "${2##*[!0-9]*}" ]; then
+        # Static GID.
+        echo "group($1) = $2"
+    else
+        # Dynamic (or something else uninteresting).
+        echo "group($1)"
+    fi
+}
+
 parse() {
     while read line; do
         [ "${line:0:1}" = '#' -o "${line:0:1}" = ';' ] && continue
@@ -8,12 +43,10 @@ parse() {
         set -- $line
         case "$1" in
             ('u')
-                echo "user($2)"
-                echo "group($2)"
-                # TODO: user:group support
+                process_u "$2" "$3"
                 ;;
             ('g')
-                echo "group($2)"
+                process_g "$2" "$3"
                 ;;
             ('m')
                 echo "user($2)"