You could also have two donation entries for the same check. It is easy to see during reconciliation because the check # and dates entered are identical. Some donor databases allow you to do it and pick the campaign/approach for the splits.  

Are you able to show them as a single transaction for banking purposes. So do a split transaction but then it only shows as one transaction on a bank deposit slip that we do as a report?

You can do this!  When you go to Add, instead of choosing Gift, choose Split Transaction.  I do this regularly for folks who send one check but donate to a couple of different funds within our database.  Makes it easy to enter and also shows it as a split transaction on reports.  However, don't forget to include this transaction type on your reports or they won't show!