Insert Specific Value Before Writing Line

GND P3559 9812, 7993 p9910.26;
GND P3559 9812, 7993 p9910.26;
46N93 P594 40898, 35899 39MIL;
PHY2_P2_CONFIG0 P2767 34205, 33537 39MIL;
18N879 P141 120461, 49324 39MIL;
PMC3_270_ETH1_D0+ P3021 8061, 44624 39MIL;

I have lines like above in my text file. I have write all this value in another text file by adding the title. In my original file's line I must check whether the line contain any MIL value if not, I must write first T1 the below T1 I must write all the line which not contain MIL value until I reach a line which Contain MIL value. If the line contain 39MIL the I must write first T5 then followed by all the line which contain 39MIL until it reach the line which contain another MIL value. Let say 50MIL. the I must write T7 then followed by all the line which contain 50MIL. I sort my original file already. so the original file will start from the line which dont have MIL to 39MIL,50MIL,75MIL and 100MIL.

My output file will look like this:
T1
GND P3559 9812, 7993 p9910.26;
TERM_RX3_2- P3347 41621, 2965 j22.49 50MIL;
58N895 P169 62611, 96124 50MIL;
ITP_TMS P200 67411, 49624 50MIL;
63N674 P175 20911, 34124 50MIL; .....