Safari for Mac: Is there a way to delete only selected Cookies?

I've yet to see this in any web browser so I'll ask if anyone else has?

I have a few web sites which I don't ever want to erase cookies for. All the cookie managers I've seen so far are always an all-or-nothing affair when clearing private data and setting privacy preferences. I need finer grained control so that I can block cookies generally yet retain cookies specifically, even across "Clear private data" selections.

For example, to get the cookies setup for my bank, I'd 'allow all cookies' for the period I'm setting up. Since cookies seem to come from many places, it's next to impossible to predict that needed cookies will come from just one particular domain. So, allowing all cookies for a time is usually necessary.

Then, I'd like to mark those cookies as "Never erase" or the like, so that no matter what I set the privacy preferences to nor no matter how many times I clear out private data, those cookies would be retained (So I don't have to re-setup accounts etc.).

Is there anything like this for Safari or Firefox?

Thanks.