question about sharing contacts and calendars between different accounts/domains

hi,


we are 2 companies with 2 domains with separate office365-accounts. both companies have the same CEO and both companies have an assistant.


now both assistants should be able to see and change the addressbook and calendar of the CEO.


for assistant #1 that's no problem, she uses the same domain as the CEO, so I only have to share both to her in the sharing-settings of outlook.


BUT the second assistant uses an different office365 with different domain, so I can't see her in the sharing-panel of calendar & contacts.


so I would like to know, how I could give the second assistant access - thx!


all users are using outlook 2011 for mac os x.


regards,




ferdinand