Add Multiple Review Dates in One Cell

I’m not sure how to start building this userform so I’d appreciate any feedback or suggestions from everyone. I’m trying to figure out a way to create a form that allows multiple date entries into one cell. This would be a record of multiple review dates for projects I’m working on. What I’d like to create is a userform that opens in the all the cells down the G3:G50 column. That form would have a checkbox or something similar that says “Review 1”. When you check that you can enter a date. A checkbox for review 2 would then show up, but would remain unchecked. If I checked the “Review 2” box, I’d like the date for review one crossed out and a new box for “Review 2” to show up. I typically review a project 3 times so I’d like the final product to look something like lines below. Again this would all be in one cell with dates/reviews stacked on top of eachother and I’m doing this to keep a record and save space. Thanks again for any suggestions on where to start on this!

X Review 1: 01/01/13 [Date Crossed Out]
X Review 2: 01/10/13 [Date Crossed Out]
X Review 3: 01/20/13
_ Review 4:

hey do you want some thing like this

Regards
CA Mahaveer Somani

This is a good way to add multiple lines in a cell, but it automitcally adds 6 lines for each combo box even if some aren't used. I was hoping to add a check box or some other item next to each combobox that would make them visible if checked. This check box would also strike out the date that was inserted in the earlier box. I would also need a text box next to each combo box that would allow for a date entry. Do you know how to do this?