Comparing array elements

hey everyone, Does anyone have and ideas of wisdom on how to compare arrays (mysql result sets) and group items based on if they exist in two or more arrays? For example: I have a table, with a list of servers: server1 server2 server3 server4 server5 ... serverX I have a table that specifies which of the servers are grouped: group1 server1 server4 server5 Now, I want to compare group1 against the server list, and do something like the following: In group: server1 server4 server5 Not in group: server2 server3 serverX <query>