There are multiple ways to accomplish your goals with AwareIM. Here are a few ideas:
1) One BO (A) that has the related BOs (B,C, etc) as references. The related BOs can be presented in tabs on BO A's form. This is the most likely answer from the example you gave.
2) A visual perspective can show info in tabs that are highly related (like references) or more loosely related. Info from BOs A, B and C could all be shown in 1 visual perspective.
3) Shortcuts. If BOs B and C are NOT "multiple allowed", the attributes of B and C can be presented as shortcuts in BO A. This will allow then to be used in forms & queries of BO A. With the example you gave, this would not apply.