Filtering usage scatterplot by attribute

I am putting together a platform usage dashboard for customer success purposes.

I have put together a scatterplot which shows total logins by date, but I would like this scatterplot to be filterable by login so that the user can see login activity of specific users.

How would I create a scatterplot that takes counts of attributes(usernames) so that I could manage this filtering?

Right now my understanding is that each X value can accept exactly one Y value, so I can only pass a pre-summed total as an integer in my current understanding.

A small snippet of my X and Y:

x=[" 2016-04-28", " 2016-04-29", " 2016-04-30", " 2016-05-02", " 2016-05-03", " 2016-05-04", " 2016-05-06"],
y=[8, 12, 6, 9, 9, 3, 13]

what I would like would be something like this:

x=[" 2016-04-28", " 2016-04-29", " 2016-04-30", " 2016-05-02", " 2016-05-03", " 2016-05-04", " 2016-05-06"],
y=[[‘login1’,‘login2’], [‘login4’,‘login8’,‘login6’], [‘login1’,‘login1’,‘login6’], [‘login4’], [‘login3’,‘login7’], [‘login4’,‘login3’],[‘login4’]]

where then the graph would count the records in each sub-list and then I could add filtering onto that count.