Do you really want EasyBCD. I do not know that, but some do use it. It has to compromise grub2's boot loader to work. You have to force grub2 to install into a partition's boot sector (PBR) which means it uses blocklists or hard coded addresses to find the rest of grub in the install. If any of those files are updated then the address may be wrong & you have to reinstall grub.
But you have to install Ubuntu's grub2 boot loader to the PBR of Ubuntu and Kubuntu's to the PBR of Kubuntu. (actually only one required as either grub will offer to boot everything.)
If you really want EasyBCD:
Whichever install you install last is the boot loader that goes into the MBR of the hard drive and will be the one used to boot. Any other boot loader must be chain loaded to another boot loader or grub can find kernels and boot those also.
How to restore the Ubuntu/XP/Vista/7 bootloader
Reinstall grub2 - Short version & full chroot version
I am not sure that burg has been maintained for a while, so it may not work with newer systems.