Hi since it seems that atm is not possible to make an ESM dependant on more than 2 esms ... and I needed to imlement in my mod some Dawnguard and future DLC stuff ... I wanted to know how can I do to add more esms ....

if not I was thinking to simply pick what I had to pick and clone all things and rename for my purpouses ... but that may end in useless extra junk data that I could just avoid by simply be able to reference the DLC esms by themselves....

The DLCs should take care of their own dependencies. Could you make the mod dependent on DG, and the game will take care of getting what it needs from the main ESM? Making a mod that uses a resource from a DLC will require that DLC to be installed, so I don't think you can just pull out the resource and make a mod with that stands alone from DG (does not require it to be installed)

the problem is version control doesnt seem to accept more than two master for my masters as references ... so how can I add also dawnguard etc?

I see that I get the same problem, I don't think its an hug issue creating new objects assuming it's not thousands. I have the same problem with my farming mod, I used copies of heathfire farming plants but want to include two Dawnguard plants, gleam and poison bloom.

Think the best solution for me is to copy two vanlia plants, change stats to match and use the Dawnguard mesh and script for the poison bloom

You could try adding or setting this line in SkyrimEditor.ini near the bottom of the [General] section:

bAllowMultipleMasterLoads=1

I have , this shol dperhaps work for a plugin , but not for a master and if I do merge those requirements with version control I loose my Esm ....

You have to make the dependancy while it's an esp. Then, when you convert the esp to an esm, the dependancy remains.