Division peak when denominator is 0

[danzigod]

Hello,

I've created two graphs for my network: "total traffic" and "number of users".

Now I want to create a graph "traffic/user". To do this, I have created a new CDEFs function to make the traffic be divised by the number of users.
But the problem is that when the number of users becomes 0, I'll have a peak. The plugin "spikekill" does not work for this because it do with the rrd files but not the function "division".

I have been thinking that maybe a script can solve this problem, by avoiding the division when the denominator is 0.
However, are there any other solutions for this problem?

If you're not clear about the question, let me know. Thanks.

[danzigod]

Any ideas?