You will want the following:
2 roles: Management (sees everything), Volunteer (see's only records with access).
Tables:
Events
Volunteers
Attendees
Details / Tasks / Requests (this should be one table, called whatever you'd like, but the action happens here).
Events --> Volunteers
Events --> Attendees
Events --> Tasks
Volunteers --> Tasks
Attendees --> Tasks
All of your volunteers will need to have their own "User" login because that is the only way you can truly filter things.
The magic to get the 'permissions' correct.
On the Volunteers table, you will have a user field for that particular Volunteer.
Create a summary field from Volunteers to Events, summarizing the number of events WITH the condition of "Volunteer User is equal to the current user".
Thus if they belong to the event, it will be "1" if not it will be "0".
At this point its easiest to convert that to a true/false checkbox; Call it something like [Volunteer Has Access]
If([# of Volunteers as Current User]>0, true, false)
Now you can pass that checkbox down as a lookup field to all the child records (Attendees, Tasks, etc.)
Then return to the role settings and set the viewing or editing permissions based on the [Volunteer Has Access] checkbox.
You can also add the logic for [Current Event] if needed as well.
