Index: trunk/Ohana/src/relphot/src/args.c
===================================================================
--- trunk/Ohana/src/relphot/src/args.c	(revision 41555)
+++ trunk/Ohana/src/relphot/src/args.c	(revision 41562)
@@ -359,10 +359,17 @@
     TGROUP_ZEROPT = TRUE;
     remove_argument (N, &argc, argv);
-    TGROUP_FILENAME = strcreate(argv[N]);
-    remove_argument (N, &argc, argv);
     // if we fit for TGROUPS, start with the images and mosaics frozen
     TGROUP_ZPT_MODE = TGROUP_ZPT_MODE_ALL;
     IMAGE_ZPT_MODE  = IMAGE_ZPT_MODE_NONE;
     MOSAIC_ZPT_MODE = MOSAIC_ZPT_MODE_NONE;
+  }
+  if ((N = get_argument (argc, argv, "-tgroup-list"))) {
+    if (!TGROUP_ZEROPT) {
+      fprintf (stderr, "-tgroup-list (filename) requires -tgroup option\n");
+      exit (2);
+    }
+    remove_argument (N, &argc, argv);
+    TGROUP_FILENAME = strcreate(argv[N]);
+    remove_argument (N, &argc, argv);
   }
   if ((N = get_argument (argc, argv, "-tgroup")) || (N = get_argument (argc, argv, "-tgroups"))) {
@@ -567,5 +574,6 @@
   if (argc != 1) relphot_usage ();
 
-  if (TGROUP_ZEROPT) {
+  // if we supplied a file, we need to load it now
+  if (TGROUP_FILENAME) {
     loadTGroups (TGROUP_FILENAME);
     free (TGROUP_FILENAME);