Can I separate two groups of vertices in an arc plot in ggraph/ggplot2 in R?

I have gotten a great graph by two distinct electrodes with the following code:

elec <- c("Fp1","Fp2","F7","F3","Fz","F4","F8","FC5","FC1","FC2","FC6","C3","Cz","C4","CP5","CP1","CP2","CP6","P7","P3","Pz","P4","P8","POz","Oz",
          "Fp1","Fp2","F7","F3","Fz","F4","F8","FC5","FC1","FC2","FC6","C3","Cz","C4","CP5","CP1","CP2","CP6","P7","P3","Pz","P4","P8","POz","Oz")

edgelist <- get.edgelist(net)
# get vertex labels
label <- get.vertex.attribute(net, "name")
# get vertex groups
group <- get.vertex.attribute(net, "group")
# get vertex fill color
fill <- get.vertex.attribute(net, "color")
# get family
family <- get.vertex.attribute(net, "family")
# get vertex degree
degrees <- degree(net)

# data frame with groups, degree, labels and id
nodes <- data.frame(group, degrees, family, label, fill, id=1:vcount(net))
nodes$family <- factor(nodes$family, levels = unique(nodes$family))
nodes$label <- factor(nodes$label, levels = unique(nodes$label))
nodes <- as_tibble(nodes)

# prepare data for edges
edges <- as_tibble(edgelist)

net.tidy <- tbl_graph(nodes = nodes, edges = edges, directed = TRUE, node_key = "label")

ggraph(net.tidy, layout = "linear") + 
  geom_edge_arc(alpha = 0.5) + 
  scale_edge_width(range = c(0.2, 2)) +
  scale_colour_manual(values= vrtxc) +
  geom_node_point(aes(size = degrees, color = family)) +
  geom_node_text(aes(label = elec), angle = 90, hjust = 1, nudge_y = -0.5, size = 3) +   
  coord_cartesian(clip = "off") + 
  theme_graph()+
  theme(legend.position = "top") 

And I got a great graph that I like.

However, I would like to separate both sets of electrodes, in the middle, where Oz is, a little bit, to see there is a difference. In the node attributes I have them differentiated by group (1,2), and I would like to know whether this information could be used to expand through the x axis both sets of vertices, on set of 25 electrodes to the left, the other one to the right of the axis, leaving a space in the middle of them.

I attach some look at the data in case its useful

> nodes
# A tibble: 50 x 6
   group degrees family label fill       id
   <fct>   <dbl> <fct>  <fct> <fct>   <int>
 1 1           5 fronp  Fp1_1 #3B9AB2     1
 2 1           9 fronp  Fp2_1 #3B9AB2     2
 3 1           6 fron   F7_1  #5DAABC     3
 4 1           7 fron   F3_1  #5DAABC     4
 5 1          11 fron   Fz_1  #5DAABC     5
 6 1           9 fron   F4_1  #5DAABC     6
 7 1          11 fron   F8_1  #5DAABC     7
 8 1           8 fronc  FC5_1 #88BAAE     8
 9 1           6 fronc  FC1_1 #88BAAE     9
10 1           4 fronc  FC2_1 #88BAAE    10
# … with 40 more rows

In case someone is interested, I ended up inserting some dummy rows in the nodes dataframe and it did the trick.