Sorry, that stupid idea will end up with fried ESC 100% and maybe motor too.
First of all it its not analog signal that goes to Motor but short impulses you cant just merge them you need somehow syncronizate them. Idealy it may work if all compnents and everything 100% indentical. Even same fets from same batch are bit different so no chance! To make 2 ESC work you need one Fet driver in other word brainboard to make work fets in sync. GriffinRu allready made it, he doubled MM powerboards and drived thems with one brainboard.
Forget it!
And if you still think that it work out dont forget to take camera and film how holy smoke escape form ESC's
