filter rows from txt

Hello.
I have a lot of txt files which format looks like:
1.
0.20
texttexttexttexttexttexttexttexttexttexttexttext
0.20
181.80
2.
14.80
texttexttexttexttexttexttexttexttexttexttexttext
texttexttexttexttexttexttexttexttexttexttexttext
texttexttexttexttexttexttexttexttexttexttexttext
texttexttexttexttexttexttexttexttexttexttexttext
15.00
167.00
3.
18.15
texttexttexttexttexttexttexttexttexttexttexttext
texttexttexttexttexttexttexttexttexttexttexttext
texttexttexttexttexttexttexttexttexttexttexttext
33.15
148.85
4.
0.05
texttexttexttexttexttexttexttexttexttexttexttext
33.20
148.80
5.
0.10
texttexttexttexttexttexttexttexttexttexttexttext
33.30
148.70
6.
0.30
texttexttexttexttexttexttexttexttexttexttexttext
33.60
148.40

As you can see, format is always:
1 number(1.,2.,3.,...)
1 number
X lines of text
1 number
1 number

And I want to filter rows to get fields containing:

But I dont know how to do it, because the number of lines of the text can be different :/

Can someone give me an advice?
Thanks