Not sure which type of nade config you use, but here's both:
Code:
//this one is for the toggle nades (so pressing once primes and pressing again releases)
alias grenset1 "bind f toggleone; bind mouse2 toggletwo; wait alias
grencycler grenset2"
alias grenset2 "bind f toggletwo; bind mouse2 toggleone; wait alias grencycler grenset1"
alias grencycler grenset1
bind x "grencycler"
Code:
//this one is for the default nades (pressing the key primes and if/when you release it, the nade goes)
alias grenset1 "bind f +gren1; bind mouse2 +gren2; wait alias
grencycler grenset2"
alias grenset2 "bind f +gren2; bind mouse2 +gren1; wait alias grencycler grenset1"
alias grencycler grenset1
bind x "grencycler"
untested, but should do what your doing (though it is getting late
)