I think I can - you mean the suffixes to the airway designators, right?
D: Advisory Service Only
F: Flight Information (Whatever that means
)
L: L/MF airway
R: RNAV route
V: VOR airway
Also, a numerical suffix can be applied in Europe which gives the so called Conditional Route Category.
Had to refer to the preamble to the almighty Jeppesen manual for F and D to be honest
I think thats about it
Have a good one, STBYRUD