mov REG1, REG2
lea REG2, [REG3 + 0x10]    

struc PRNG val*

        ; your favorite prng function goes here

        . = rnd mod val
end struc

myRnd PRNG 6 ; need to get a random number in range [0-5]
iterate <REG1,REG2,REG3>,\
        eax,ebx,ecx,\
        eax,ecx,ebx,\
        ebx,eax,ecx,\
        ebx,ecx,eax,\
        ecx,eax,ebx,\
        ecx,ebx,eax

        indx myRnd+1
        mov REG1, REG2
        lea REG2, [REG3 + 0x10]
        break
end iterate    

I need to replace REG1, REG2, REG3 with random registers (without repeating) so i need a macro which assigns the registers to REG1, REG2, REG3. For example:

REG1 replaces to eax
REG2 replaces to ebx
REG3 replaces to ecx

macro name REG1, REG2, REG3 { mov REG1, REG2
 lea REG2, [REG3 + 0x10] }    

list1 equ eax,ebx,ecx
list2 equ ebx,ecx,eax
...
macro name_call index {name list#index}