ActionScript 3.0 :: Use ClearInterval(b) Under Certain Conditions To Stop Each Interval?

I am using setInterval to call a function which itself creates intervals to call a second function..My issue is with the second interval in function1 'var b'. I am trying to use clearInterval(b) under certain conditions to stop each interval. This works when I have a 'single' interval created (i.e function 1 is only called once) but as soon as it is called more than once, I get errors.simple eg below

Code:
var b:uint;
var a = setInterval(function1, 1000);[code]....

I actually solved this by creating a 'counter variable' which is passed to function2, and just used clearInterval(counter), counter++; to clear each interval.My issue with this solution is having to keep track of what number interval im up to 'manually'.. and if i create more intervals later on Im worried about 'loosing count' and having to keep track.. and would rather reference the var name itself if possible?

I've tried to compare my counter var to the value of the interval via a trace, and they appear to be the same. So I dont understand why clear(a) and clear(counter) dont give me equivalent results.