There is no such option. As a workaround, maybe you can run a piece of Labtalk script to detect those adjacent data points and insert an empty row between. Then make the plot. Suppose Col(A) is your x column, you can go to menu Window:Script Window. Copy paste the script below, highlight all lines and click Enter to run. See if empty rows are inserted.
for (int i = wks.nrows; i>0; i--) {
if(col(A)[i] == col(A)[i-1]) {
wks.insertRows(i);
}
}
James