Can I authorize 2 apple IDs on one computer?

I'm new to the communities so please bear with me if I post this inappropriately.

My husband and I both have iphones. My two children have itouchs. My husband has an ipad. We also have numerous ipods.

We have two computers in the house. When my husband first bought an ipod, we had a PC. All of his devices have always been synced on the PC using his apple id. When I got my iphone, I synced on our MAC using my apple id. When the kids got itouches, they synced on the MAC using their apple id.

We discovered that anything the kids and I purchased on itunes on the MAC is available to all of us.

We would now like to use home sharing. To do this, both computers must be authorized to one apple id. If the PC is deauthorized for my husband's apple id, I understand he will lose his purchases on the PC (or at least they won't be available until he authorizes it again).

I understand that an apple id may be authorized on up to 5 computers. But what about multiple apple id on one computer???

My questions are basically this...

Can we authorize 2 or more apple id on one computer?

Can I authorize my apple id on the PC and have my husband's apple id remain authorized on the PC?

Can my husband's apple id be authorized on the MAC and my apple id remain authorized?

Can the kids apple id be authorized on each of the PC and the MAC?

Can we have 4 different apple id authorized on a computer at once?

Will authorizing my apple id on the PC de-authorize my husband's apple id?

How's that for asking the same question in lots of different ways? I have seen a lot about a computer using the same id multiple times but nothing about whether I can authorize many different ids on one computer at once.

Thanks for the help.