The best replacement for aggregation is composition.

The best alternatives to aggregation are rated as following:
★★★★★  composition
★★★★  inheritance
★★★★  association
★★★  composition uml
★★  agglomeration
★  containment
★  flocculation
★  generalization
★  composition c++
★  composition java
★  trunking
★  coagulation
★  congregation
★  ternary relationship
  composition c#
  agglutination
  association uml
  generalisation
  consolidation
  layering
  etherchannel
  mpio

Your alternative for aggregation is not listed? Suggest!
Speaking about aggregation, one probably shouldn't forget about managed switch.

Other search terms related to aggregation and their ratings are:
★★★★★ managed switch
★★★★ switch
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aggregation
composition
inheritance