Data extraction from complex database

[OldStudent]

Given the following snippet of a database:

[TABLE="class: grid, width: 500, align: center"]
<tbody>[TR]
[TD]sample #[/TD]
[TD]XDAT[/TD]
[TD]Horiz[/TD]
[TD]dy[/TD]
[TD]#[/TD]
[TD]max dy[/TD]
[/TR]
[TR]
[TD]1446[/TD]
[TD]211[/TD]
[TD]201.2[/TD]
[TD]98[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]1447[/TD]
[TD]211[/TD]
[TD]202.2[/TD]
[TD]68[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]1448[/TD]
[TD]211[/TD]
[TD]203.0[/TD]
[TD]50[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]1614[/TD]
[TD]200[/TD]
[TD]135[/TD]
[TD]40[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]1615[/TD]
[TD]200[/TD]
[TD]136[/TD]
[TD]45[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]1616[/TD]
[TD]200[/TD]
[TD]130[/TD]
[TD]35[/TD]
[TD][/TD]
[TD][/TD]
[/TR]
</tbody>[/TABLE]

I would like to automatically fill in the "#" and "max dy" columns as follows:

Filled in part of previous snippet as desired:

[TABLE="class: grid, width: 250"]
<tbody>[TR]
[TD]#[/TD]
[TD]Max dy[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]98[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]45[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD][/TD]
[/TR]
</tbody>[/TABLE]

1 - the # value should stay until any of the following conditions is met:
a) XDAT value changes
b) Sample # is not sequential
c) 36 columns have been given same number (it should then increase by 1)

I would then like to create a table of the "Max dy" - one for each 'set' as defined above. There are four different XDAT possible values.

Note - the reason the sample #'s miss values (intentional) is that the columns have been filtered.

Thank you in advance for your help. This is a great assistance on a very important project.