Overflow analysis

Hello,

Can anyone help me? I would like to find out a way of working out the traffic on one particular trunk in a group. An example of my problem is:

If I offer a trunk group 3.4 Erlangs, which is the first member that will carry less than 0.1 Erlang. I know the answer is trunk 8, which carries 0.07 Erlangs. I worked this out by repeatedly modelling a trunk group with an increasing number of lines using Erlang B, but I would love a simple way to automate this without having to repeatedly apply an Erlang B formula (I’ve tried it, and for large trunk groups, it’s very slow).

I am doing this for overflow analysis. I would appreciate any help.