Multicast Group Members on Different Port Numbers – Is It Possible?

The main benefit of hashing rather than a simple compare is that you can do one lookup for any number of enabled multicast addresses. The system that has an exact match for 80 addresses will either have to build logic to fetch 80 addresses into a comparator in turn, or have 80 comparators in parallel. That's a lot of gates, even if it is simple in concept. And that's all extra cost and power.

In contrast, a hash lookup can be easily implemented with a shift register and a few XOR gates. The computation and shifts can be done as the bits arrive on the wire. Even better, the NIC is doing this already, in order to calculate the checksum.

Note also, that Stevens was writing 20-25 years ago; whilst it is still more or less the definitive work on TCP/IP, hardware has come along since then. The cost of adding a few thousand more gates won't make so much difference. Flicking through a few NIC datasheets, most opt for a hybrid approach: e.g. 16 exact addresses and a 4096 bit hashtable.

Switches are not like hubs. Hubs repeat every frame out every port. Switches selectively send the layer-2 frames to the port where the receiving host is connected.

Switches are layer-2 devices, so they only look at the layer-2 frames, not the layer-3 (IP, etc.) packets, or the layer-4 (TCP, UDP, etc.) segments. Switches learn the MAC addresses which are connected on each port from the traffic through each port, and they only send frames destined for a MAC address on a port to that port. Switches will flood broadcast frames to every port (but that's the point of a broadcast, it is destined to every host on the broadcast domain), as well as unicasts which are not yet in its MAC address table.

The HPE 1920-8G-PoE+ is also a layer-3 switch. Layer-3 is where you will find IP packets, but layer-3 routing only sends IP packets to the ports which have the network of the destination IP address.

You didn't include any configuration, but I seriously doubt you have a problem with traffic which is not destined to a host connected to your WAPs traveling to your WAPs.

Edit:

Based on your comment about this being multicast, you need to use IGMP snooping to deal with your problem. Multicast frames, like broadcast frames, are usually sent to all switch ports in the same broadcast domain. IGMP snooping lets a switch snoop on IGMP messages to determine which switch ports should receive frames for which multicast groups. Your switch supports IGMP snooping:

• IGMP snooping

improves network performance through multicast filtering, instead of flooding traffic to all ports

You could also break up your layer-2 broadcast domain with VLANs.