Multiple membership price by number of users (using Extras dropdown)

Being able to "multiply" the membership price by a number of users (extras).

Now one has to flood the database extra values tables with hard coded amounts for every other extra, and this for every membership. I know it's possible to add a few extras in a dropdown, but not for like say 100 values.

Plus the price need to be set for each extra value, there's no "multiplication" setting for the extra dropdown.

For example:
My membership price is $2 USD. This is the standard price for 1 user.
If I want to give the user the option to buy this membership for 10 users, I would have this option rendered in a dropdown. Where the values would be generated using multiplication (e.g. $2 times 2 users = $4 ).