Custom Module - dependency between Account and Contact

Custom Module - dependency between Account and Contact

We'd like to record key Interactions so they are elevated above the general day to day clutter of tasks etc. This will help us to manage our relationships with our customers. An interaction will take place between one of our team and our customer (Contact and Account).

I'd like to be able to specify the Contact and have the system populate the Account or Vendor from the Contact so that they show up in the Account or Vendor related lists. I can't find a way to do this.

Is it possible?

By adding both fields as lookups I can specify a contact from one account and add a completely different account - introducing the possibility of errors in the data.

Thanks,

Linda