Android Contacts & "Exchange"

[stevenrw]

Hello everybody, its me again...
I'm struggling to find an explanation for the "Exchange" field in Android contacts. I'm looking at Samsung Kies with my Samsung phone attached and there are various tabs depending upon where the contact was synched from.
I'm assuming the only reason that some are showing under the "Exchange" tab is because they were synched from my Microsoft (Hotmail) account.
So, this isn't really a "group" as such. I'm trying to spring clean my contacts and I'm struggling to see the actual point of splitting all these up.
I can appreciate splitting contacts up into groups like "tradespeople" "Family" "Friends" etc, but the fact that these are first divided into these tabs (like gmail contacts)etc just over complicates it.
I know Kies ain't exactly a triumph when it comes to file management but there must be an easy way to just merge them into one surely?