Virtual network and Person NS

[dreshkov_imported]

I have a 'problem' (I don't know really is it a problem) working with CRM in Axapta 3.0 SP1.
When I add new contact person or employee the number sequence Virtual Network / Person grows by 2 sometimes by 3.
Can someone explain me what is this number for and am I supposed to worry about its growth or just to make the sequence big enough?
I can't really catch the idea if this virtual network - some hints?!

Thanx!