if in a current ac, there are 6 Directors and 5 Auth sig

I guess you are posting wrong question in the forum. Is it possible or not that you have to check with the Bank. Your Banker will inform you the process and whether the same is permissible or not as per RBI Guidelines.

How do you expect lawyers to tell you that whether Net Banking to all the Directors can be given or not?

I completely agree with learned expert Mr. Rohit dalmia, Advocate. Your Banker is the best person to resolve the issue straightaway.