pagination within grouped data

[eluser]Hoopoe[/eluser]
This is an "in theory" question.

Take some tabs A, B with sub-tabs a1, a2 and b1, b2

a1, a2 are records, belonging to the category A: similarly for b1 etc.

Details are the values of the fields in each record.

A
- a1 > details
- a2 > details
B
-b1 > details
-b2 > details

I can envisage implementing pagination in each category i.e if total grouped records > greater than per-page, then show pagination as another <li> element.

The question I have is as follows:
If category A has enough records to require pagination, and I click the links to page#2 of the A records, what happens if I click on tab B if category B has no page#2 ?

Clicking on tab B would surely display an error.

My assumption is that I'd need some Javascript to do the following: whenever clicking on a category tab (A, B) rather than a record tab (a1, b1 etc), set the $start value for pagination to 0.

I'm aware this question is a bit abstract but would appreciate any thoughts anyone may have on the subject.

Hoopoe