diff --git a/server/src/gtfpga.c b/server/src/gtfpga.c
index d6746fe61..bd579756e 100644
--- a/server/src/gtfpga.c
+++ b/server/src/gtfpga.c
@@ -35,6 +35,12 @@ int gtfpga_parse(config_setting_t *cfg, struct node *n)
 	config_setting_t *cfg_slot, *cfg_id;
 	struct gtfpga *g = alloc(sizeof(struct gtfpga));
 
+	/* Checks */
+	if (n->combine != 1) {
+		config_setting_t *cfg_combine = config_setting_get_member(cfg, "combine");
+		cerror(cfg_combine, "The GTFPGA node type does not support combining!");
+	}
+
 	pci_filter_init(NULL, &g->filter);
 
 	if (cfg_slot = config_setting_get_member(cfg, "slot")) {
diff --git a/server/src/opal.c b/server/src/opal.c
index c9b08ec98..5184ccff7 100644
--- a/server/src/opal.c
+++ b/server/src/opal.c
@@ -114,6 +114,12 @@ int opal_parse(config_setting_t *cfg, struct node *n)
 {
 	struct opal *o = alloc(sizeof(struct opal));
 	
+	/* Checks */
+	if (n->combine != 1) {
+		config_setting_t *cfg_combine = config_setting_get_member(cfg, "combine");
+		cerror(cfg_combine, "The OPAL-RT node type does not support combining!");
+	}
+	
 	config_setting_lookup_int(cfg, "send_id", &o->send_id);
 	config_setting_lookup_int(cfg, "recv_id", &o->recv_id);
 	config_setting_lookup_bool(cfg, "reply", &o->reply);