input bus for push buttons

I want to use siemens logo 8 for my home automation.

But one thing is missing for me is there a way to get this function:

I want to link all my pushbuttons in home so i don't need a cable for every button.

But this so cheap possible. Dobiss has this function verry cheap with a ftp bus and bus couplers for only €5 . 

But i want to use siemens logo, need some help

thanks for your reply

but knx ist't cheap for every button its about €40