projects, teams & systems (oh my...)

[Dion Jones]

So, time for a Jira spring clean and I'd like some advice on getting things running more smoothly.

Here is what i need to represent in Jira:

• We have "systems" a,b,c and teams associated with those systems
• We have a separate Business Analysis team through which all change is filtered
• We have a separate testing team, through which all testing is pushed
• We have projects.  Some of which are cross system team, others are not
• We have feature requests - some of these are also cross system team, others are not
• We have bug reports

So - my questions are:

Where do epics sit?

should there be projects for all teams?

Should we create a project based around an epic, if it is cross systems?

if there is a good article on this kind of stuff, please point me at it and i'd like to hear some other people's approaches to organising this kind of thing..