You can use a 'switch' but NOT a 'hub.' The Waves APA user manual states the following (which is long, but worth considering):

There are two possible ways to connect the APA32 unit to your host computer: 1. Direct connection to the host computer’s Ethernet socket using the supplied crossed Ethernet cable. 2. If you intend to connect more than one APA32 unit to your host computer, you will need to connect the APA32 units to an Ethernet switch* (not a hub) and connect the switch to your host computer using standard (non-crossed) Ethernet cables.

If you connect more than one APA32 unit to your host computer, the Ethernet card in your host computer needs to be 1Gbit bandwidth based in order to support the required network communication bandwidth.

Important Note: It is possible to connect the APA32 unit(s) to an existing Ethernet switch used to connect your host computer to other network applications. However, due to bandwidth and other network considerations it is highly recommended to separate networks and to connect your APA32 unit(s) to a dedicated Ethernet card. Following this recommendation will ensure fulfilling the maximum power and potential of your APA32 unit(s).