need seriouse help with devloping a tree based apllication

[brainstormflash]

hi , I'm pretty new to php and i need some help about how to approach a project I have.

well it goes like this:

 

I need to build a pyramid structure - "game".

where there is a father-child relationship between nodes.

each node is a player that should have its own properties such as accumulated points, email address etc.

another important point (perhaps) is that each rank in the tree has it's own considerations.

 

I don't expect you to tell me how to build it of course,I just don't know how to approach it.

 

should I base it on XML?

should I use objects to structure it ? where do I store those objects?

should I use a database? multiple databases?

all of the above?

 

I'm confused....

thanks for reading.