So these were the groups we'd found:

(b,c,m,p), (d,g (all combos tested)), (l,n,r,s,t), (h,v,w,y), (q,z)

with f,j,k,x left

checking against scrabble:

vowels are 1 point

l,n,r,s,t are 1 point

d,g are 2 points

b,c,m,p are 3 points

h,v,w,y are 4 points

q,z are 10 points

and the remaining ones...

f is 4 points

j,x are 8 points

k is 5 points

Just for Tibs...

(b,c,m,p), (d,g (all combos tested)), (l,n,r,s,t), (h,v,w,y), (q,z)

with f,j,k,x left

checking against scrabble:

vowels are 1 point

l,n,r,s,t are 1 point

d,g are 2 points

b,c,m,p are 3 points

h,v,w,y are 4 points

q,z are 10 points

and the remaining ones...

f is 4 points

j,x are 8 points

k is 5 points

Just for Tibs...