Creating groups from a list based on conditions with the maximum amount of variation

this might not make any sense so please ask any questions necessary to understand.

So I have a list of 28 people and have conditions for two categories. I need to place these people into groups with as much variation among their associated conditions within each group as possible. This is for a conference so I want to create diverse groups for each day so that everybody isn't in the same groups with the same people each day, and that they are also diverse based on these two conditions. There will be 4 days worth of groups. Days 1, 2 and 4, I need 7 groups of 4. Day 3 I need 8 groups of 3 and 1 group of 4.

Columns B and C are the conditions. Each person has a location and tag, and I want the groups to have as much location and tag diversity as possible.