Have you tried:
Edit > Preferences > Name Resolution > Check enable MAC name resolution.
This should then show the word "Cisco" in the mac address of all Cisco devices.
Alternatively, I would think you would need to build an expression like:
!(eth.src == 00:1b:8f:37:1a:88) and !(eth.src == 00:1b:8f:37:1a:87)
There is instructions in the help file for using partial macs and / or IPs instead of full IPs and / or macs.