Build specific targets of a sub-makefile (inspired by Gruntjs)

I recently had a great idea:
When I was using gruntjs a couple of months ago, I was introduced to the possibility of sub-targets there. Those were specified using colons (":") to seperate parent target and subtarget. Since I am using dedicated sub-makefiles for single modules in my project, I just had the brilliant idea: realize something similar to access goals from those. This saves me the trouble of specifying the file used and to define necessary environment variables by hand.

So what I came up with initially and what worked out quite well, was this:

# idea from http://blog.jgc.org/2007/06/escaping-comma-and-space-in-gnu-make.html 
# I put this in my dedicated defs.mk file for general usage
 ,             := ,
 space         :=
 space         +=
 $(space)      := 
 $(space)      +=
   
 $(PROJECT)\:%:  
      $(eval SUBGOALS := $(subst $(,),$( ),$*))  
      $(PRINT) making $(PROJECT) with goal\(s\) $(SUBGOALS)...  
      $(MAKE) -f "$(abspath $(ROOTDIR)/Make/$(PROJECT).mk)" $(SUBGOALS)  
      $(PRINT) done making $(PROJECT) with goal\(s\) $(SUBGOALS)  

Here is an example, of what the benefit of this is:

$: make modulexy:libxy,binxy
making modulexy with goal(s) libxy binxy...

There is one problem, though: While you CAN run makefile goals in any recursion level
(e.g. $: make goal1:goal2:goal3: ...)
only the first level allows you to pass the goals together to a single instance of make. Things like
"$: make goal1:goal2:goal3.1,goal3.2"
will be executed as
"make -f goal1file goal2:goal3.1 goal3.2"
That means, the command tries to run goal3.2 in goal1file (the file belonging to goal1).
The workaround would be
"make goal1:goal2:goal3.1,goal2:goal3.2"
which is then causing two instances of make being run on the makefile belonging to goal2: One for goal3.1 and one for goal 3.2.

So far, I did not feel the need to improve this (by adding a way to evaluate brackets, for example. Imagine "$: make goal1:goal2:(goal3.1,goal3.2)"). But if you are in a desperate need of this, it will be hard to achieve with make-internal tools only. sed will probably be your friend, here.
Contact me, if you come to a solution, so I can add it here.

See you soon!