| Leaving aside the suggestion of goldberging something together, the answer is no, for the above stated reason that foil sockets have only 2 terminals, while 3 are needed for epee.
Now, if for some reason the voices in your head are insistent that you kludge up an epee connector that incorporates a LP bayonet socket, so long as what you devise meets the conditions in the rules (doesn't project out beyond the edge of the guard, provides a secure connection with a retaining device, can not be readily shorted, allows easy checking of the connection), any type of connector is legal.
If your objective is to have a universal cord so that you don't need to either change cords or wear two cords when fencing foil and epee concurrently, the simpler approach would be to just use an epee socket in the foil with the wire running to the B-line, and then connect a crocodile-clip lead in parallel with the A-line out of the reel-end plug of an epee bodycord. There would be a risk, in foil, of a touch that lands right on the A-terminal on the socket registering a valid touch against you.
-Dave |