I personally prefer to have most if not all of my Menu, Toolbar, and Ribbon macros load / execute a LISP routine, because there's so much more flexibility.
That said, here's a simple LISP routine that will open a new drawing, from a found drawing template, and activate it:
Code:
(defun _NewDWGFromDWT (dwt)
(vl-load-com)
(if (findfile dwt)
(vla-activate
(vla-add (vla-get-documents (vlax-get-acad-object))
dwt))
(prompt "\n** Template cannot be found ** ")))
... A simple Macro for each drawing template should do the trick - just be sure to supply the appropriate File Path to the function as an argument. If your drawing templates reside in the Support File Search Paths (SFSP) then only a File Name should be required.
HTH