Non alphabetic sorting

In a League Table report I have the following layout
Season Header - Group on 'Season' (EG 1948)
League Header - Group on 'League' (A to Z)
Detail - Sort by 'League Position'

In the table, the League name comes from a separate table and on the
Input form is available from a Drop-down control that is an after
event of picking the season 'year'

Leagues are ranked in the real world by importance (Senior teams,
junior teams, trainee teams etc)
I input data each year in that order

My problem - I want to sort the Leagues such that the report outputs
in the order I have added them to the table (is this not a wise
strategy?) rather than the Alpha A-Z sort
For example
for a particular year, I might have
Natoinal League 1
National League 2
Metropolitain League

This is their order of seniority, but at present the Metropolitain
League is printing as the first (as letter 'M' is ranking above 'N'

What's the best strategy to remedy this/rank in the order I want them?

Thanks
Neil