looking for help with auto creating rules with eval hierarchically

[PATTON, BILLY \(SBCSI\)]

I have to create rules , 555  currently with perl, that make use of
lists.  Not all lists are the same size.

Here is a sample of 2 of the of the list (currently I have 87, but that
will increase)

PROJECTS := \
            lde \
            ldm \
            ldf \
            ldg \
            ldw \
            lbf \
            ldb

BB_lde := \
          ld_exp \
          ld_bch

BB_ldm := \
          ldmrbcomc \
          ldmrbc \
          ldmrbcomg \
          ldmmdc \
          ldmcolc \
          ldmapc \
          ldmmdg \
          ldmcomc \
          ldmcolg \
          ldmapg \
          ldmcomg

TOPIC_ldm_ldmrbcomc := \
                       rfc

As a sample example I created this
proj := lde ldg ldm ldf ldw lbf ldb
.PHONY : all ${proj}
define dummy_template
 $(1): ; @echo $(1)
endef
all : ${proj}

$(foreach var,$(proj),$(eval $(call dummy_template,$(var))))

$(filter-out ldb,${proj}) : ldb


This works fine for proj alias PROJECTS
Now looking at each of the PROJECTS I  need to create the same thing
$(foreach var for each of the
BB_<proj>  But I don't want to hard code all the names.  This needs to
be expandable in the future
This will then be further created for the TOPIC_<proj>_<bb>

My first best try
$foreach proj,${PROJECTS},

Will give me the list names
$(addprefix BB_,${PROJECTS})

So would it be something like
$(foreach proj,${PROJECTS}  # to capture project name
  , $(foreach bb, $(addprefix BB_,${proj})) # name of list BB_<proj>
  , $(eval $(call dummy_template, ${bb}))  # call define
 ) # foreach 


If this works. Can I put comments as I have above.
If I don't document this VERY well, I'll neveru figure it out 6 months
from now.