Linking meetings to accounts and/or opportunities

In that scenario the Meeting belongs to Opportunity's relationship, not to the Account's one.

A Meeting can only be related to a single record at once, that means, or it is related to an Opportunity or to an Account.

In order to make that Meeting to be displayed in subpanel under both Opportunity and Account you need to duplicate it, which may not be a good approach.

Another approach is to create a relationship One to Many between Accounts and Meetings. Then you will need to create LogicHook after_save on Meetings in order to relate new Meetings to the Account thru that new relationship if the Meeting is related to either Account or Opportunity thru default relationship (parent_type, parent_id). Finally you will need to override the default meetings subpanel by the custom one.

Anyway, it sound quite hard to accomplish for some very specific request.

In that scenario the Meeting belongs to Opportunity's relationship, not to the Account's one.

A Meeting can only be related to a single record at once, that means, or it is related to an Opportunity or to an Account.

In order to make that Meeting to be displayed in subpanel under both Opportunity and Account you need to duplicate it, which may not be a good approach.

Another approach is to create a relationship One to Many between Accounts and Meetings. Then you will need to create LogicHook after_save on Meetings in order to relate new Meetings to the Account thru that new relationship if the Meeting is related to either Account or Opportunity thru default relationship (parent_type, parent_id). Finally you will need to override the default meetings subpanel by the custom one.

Anyway, it sound quite hard to accomplish for some very specific request.