I'm sure it is possible.  The real question is not "is it possible" but "how do I ..." .

This would be fairly involved and complex in a data base.  There isn't a specific example here to do just that.
BUT there are examples in the courses and in the TechHelp or FastTips videos that have the pieces to help you put it together.  Maybe not exact but Richard teaches the methods.
One quote from him is, "I give you the Lego pieces, it is up to you to put them together to meet your needs".

The first step would be to identify your needs.  Then on paper or in a word document or note cards, identify how you do those tasks now manually.  Third, start converting your paper copy to Access.

See the Normalizing Data video as well as Access Beginner 1 how to start developing a system for you.
Do a search of the topics you listed in the search box above.  Leads, contacts, appointments, etc.

"Network marketing" is another name for multi-level marketing, or MLM, the controversial marketing "pyramid" scheme that is unsustainable in itself.  Basically, you recruit sellers, and those sellers recruit other sellers, etc.  It's unsustainable because you go down a few levels of this pyramid and you exceed the *world's population*, and surely not everyone (not even close to everyone) will benefit.  And no good database can be built from such a suspect business model.