how can I build twin complex of complex of two proteins? (A:B) + (A:B) = (A:B:B:A)

Question

[Xylanaser]

hey I need to build complex of two heterodimers, i know that homologue complex pdb assembles in that way.
In short: (A:B) + (A:B) = (A:B:B:A) Can you help what program could i use? cheers