I think that we probably will end up talking off-line about this but I do know how to set this up with about an hour of set up time. Basically what you want to do is put your opportunity quote and focus for that particular user.
Sometimes I call this my "shined the light" method. Basically we push a button and it either edits or adds a record to a table of users where the key feel this user. Then using a relationship where the reference field on the right hand side is the current user by formula we can flow that focus opportunity down to any child table that we need.
Then that button writes the record ID of the opportunity to that record. That That allows us to have the opportunity "lit up" for that particular user. That light then flows down to the groups which are on the opportunity which flows down to the group items which then flows up to the items. So now we have the items illuminated and when we are going to add an estimate we can pop up a report which only offers up the illuminated items.