Complex Case Expression - Combine Two Statements To Get Desired Bucket

I have a case expression as follows:

(CASE WHEN DATEa=DATEb THEN 0
WHEN DATEa> DATEb THEN NETWORKDAYS(DATEb, DATEa)
WHEN DATEa < DATEb THEN NETWORKDAYS(DATEa, DATEb)
WHEN STATUS='PENDING' THEN NULL
ELSE NULL
END) AS RESULTa,

Now what I need to be able to do is place those results in buckets, similar to this:

(CASE WHEN RESULTa < 0 THEN '<0'
WHEN RESULTa between -1 AND 6 THEN '<=5'
WHEN RESULTa >5 THEN '>5'
ELSE ''
END) AS BUCKETa

I understand that I can't call an alias from a previous case expresson to get these desired results and how I could combine the two statements to get the desired bucket.