Is there a way to create a collection of collections?

e.g. I created a collection ListOf(Lines)
After I add all my lines to it, I want to store this colleciton in another listOf(Collections). The reason I want to do this is because i want to create several separate collections of lines and I'll need to loop through them all to look for a certain line and I thought this would be a good approach if it's possible.

i tried to create a listOf(Collection) but when i try to add my listOf(Lines) to it, it complains because the list is a colleciton of lines.

thanks,
Proctor