Count Unique Values

Can I figure out a Count of unique values?

I have a Units Object which lists parcel number and address and owner

0140-3333-300-01 1234 Main St #1, Owner=Tom Jones

0140-3333-300-01 1234 Main St #2, Owner=Tom Jones

0140-3333-300-01 1234 Main St #3, Owner=Tom Jones

0140-3333-300-01 1234 Main St #4, Owner=Tom Jones

In an Owners Object, I want it to say 1 under # of Properties and 4 under # of Units. Unique parcel numbers would tell me how many properties.

Thanks for any tips,

Tim