mouse over ToolTip for list page

I have tried without success to add a tooltip to a field on the list page using a field value from another table
and have reverted to using a custom value - ie. doing an sql query and modifying the list filed by adding a field value from
another table. This works, but is not an ideal solution.

I would like to be able to add a mouseover event to show a tooltip on the list page.

e.g. a customers list page... when the mouse is over the account_id field, I would like to show a boat name which is from another
table - linked on account_id

is this possible ?