eh, I suggest you re-map your conrol settings,
if it's giving you a hard time, fix it, move keys where theye'er accessible,
assuming you're running n64 >>
anyway, multi key button is possible,
use N-Rage Input Plugin (2)
on the modifier's tab, click new modifier, highlight(click the newly created item)
and the right pane should be enabled, on the right pane,
select "macro" from the list, the set of n64 controls, check which buttons you wish to be pressed (multi key) to bind on the assigned key.
apply and you're done.
if you fancy, here's my gba and n64 controls (usually I'd play through my controller)
GBA, GB\C
D-PAD-> WASD
Sel & Start -> C, V
A & B -> numpad 2, numpad 1
L & R -> numpad 4, numpad 5(or 6)
n64>>
Analog -> WASD
D-Pad -> depend's on the game, (move it to Wasd or use TFGH)
A & B -> Numpad 2, Numpad 1
Z -> Numpad 0 (Ins)
L & R -> Num 4, Num 6 )or Q, E
C-Buttons -> Play around with it, Either Arrow Jeys or the spare buttons at the Numpad.