python packages cross references

[Roman Yakovenko]

Hi. I need help( or solution :-) ). 
Problem: my project has 3 packages
prj
 +------A
 +------B
 +------Utils

The question is: what is the right way to use functionality from Utils in A and B packages ?
I know that after importing package I know it's location, but it doesn't help me in any module within package A or B.
I can add full path to prj to sys.path but it seems to be the wrong way. 
May be I missed something? 

Thanks.

Roman