You should be able to continue the sequences directly in your existing -f
specification.
To skip both 5 and 7, try:
cut -d, -f-4,6-6,8-
As you're skipping a single sequential column, this can also be written as:
cut -d, -f-4,6,8-
To keep it going, if you wanted to skip 5, 7, and 11, you would use:
cut -d, -f-4,6-6,8-10,12-
To put it into a more-clear perspective, it is easier to visualize when you use starting/ending columns which go on the beginning/end of the sequence list, respectively. For instance, the following will print columns 2 through 20, skipping columns 5 and 11:
cut -d, -f2-4,6-10,12-20
So, this will print "2 through 4", skip 5, "6 through 10", skip 11, and then "12 through 20".