Merge Partitions disk0s2 and disk0s4 (leaving disk0s3)

Dear all,

As the title says, I need to merge disk0s2 and disk0s4 without touching disk0s3 as the latter is my recovery partition. I have not dared to try, but I guess I cannot use this command in terminal since it also merges disk0s3:

diskutil mergePartitions JHFS+ NewName disk0s2 disk0s4

right now when I type the "diskutil list" command I get this:

asger$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *320.1 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 278.5 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

4: Apple_HFS BOOTCAMP 40.6 GB disk0s4

As I am using El Capitan, disk utility does not work either because apple changed it to a useless poor beta like program on El Capitan.

I have considered just typing the above merge command and then somehow reinstall the Apple_Boot Recovery HD, But I really don't want to go down that road if possible.

And no, Bootcamp assistant can't do it since the Bootcamp partition is already erased and formatted into JHFS+.

Any suggestions?