To answer your first question, yes this is possible.
For example, to link to a calendar that has been shared to you:
- In Calendar view, right-click on the Calendars heading (immediately beneath the New Calendar button).
- Click Link to Shared Calendar
- Enter the email address of the account that created the share
- Type in the path to the shared item - usually just the name will suffice.
- Click OK
You can use the zmmailbox command to create mount points.
Here's an example Perl script will get members of a distribution list (email@example.com) and mount the folder Calendar on firstname.lastname@example.org as Shared in each member's account.
If you have a search on the forum for "createmountpoint" you'll find loads of other examples for different situations.
# Get distribution list information and filter to just it's members
my $gdl = `/opt/zimbra/bin/zmprov gdl mydistlist\@example.com|grep zimbraMailForwardingAddress:`;
my @dlmembers = split('\n', $gdl);
$member =~ s/zimbraMailForwardingAddress:\s*|\s*$//g;
print " - Got member '$member'.\n";
system("zmmailbox -z -m $member createMountpoint --view appointment -F# /Shared email@example.com /Calendar");