You may use a device called a "print server" to attach a printer to a network connection. Some printers already come with print servers installed, but these are usually the more expensive business types.
The print server should be able to support "workgroup" or "peer-to-peer" printing.
Make sure your O/S is supported.
Hooking the scanner to the network is a bad idea.
(1) Getting network support in a scanner means you are paying $$ for business features you do not need in the home or SOHO.
(2) Most business scanning is OCR. Most home scanning is graphics. Graphics are data intensive and a direct connection is necessary for quality color, contrast, and saturation control.
(3) The usual scanner interfaces in order of preference are: [1]USB [2]SCSI [3]Parallel.
Conclusion: Forget the dedicated network attachments for the printer/scanner and spend that extra $$ on better peripherals!
The most cost efficient solution for the 2 person network is to dedicate the most powerful of the computers to be the scanning/print station. Print jobs would be handled transparently w/o user intervention.
Scanning tasks would be done on the local computer, then the finished scans would be placed in a shared folder for the second person to retrieve.