I have a large number of song lyrics that I need to sort (according to the first few words of the first line). Here is a sample:

aDiyavar virumbum. rAgA: kuntalavarALi. Adi tALA. A.S.Krishnamurti & Shanta Radhakrishnan.

P: aDiyavar virumbum Ayar tam kozhundE un padamalar pOTriDa varam aruLvAyE
A: murppirappil un porppadam paTriya arasa riSi avan mukakundan
ippirappum avanaik-kaiviDalinri narppadam kATTiya namdakumArA
2: pankaja vizhiyOi sondamenrE unakku konju tamizhil sErndisai pADi
tanjamenru undan tiruvaDi paNindE sanjIvAmrtam santamuDam paDittiDum

Each song has the same pattern (the number of lines may differ) and the songs are separated by 3 or 4 spaces.
Is there an easy way to do this? Thanks