- assigned to me, and
- assigned to groups that I am a member of
The Where clause for the view needs to be:
<Or>
<Membership Type="CurrentUserGroups">
<FieldRef Name="AssignedTo"/>
</Membership>
<Eq>
<FieldRef Name="AssignedTo"/>
<Value Type="Integer">
<UserID/>
</Value>
</Eq>
</Or>
And that is all.