Wireless Time Machining for multiple Macs on Home Network

Solution needed: Automatic background Time Machine backups for multiple Macs in an all wireless environment without having external drive connected to ALL of the computers. Hardwire connection to one would be fine.
Current environment: Two iMac, One Macbook, plus some PCs, and other devices connecting wirelessly to Linksys E4200 to Internet. Macs are running Maverick.
Additional Requirement: Don't want to lose current parental control ability. The OSX parental controls were too buggy for me to use consistently. I used the router instead for time restrictions and OpenDNS for some content restriction/blacklisting.

I had been just using an external drive on ONE iMac (mine) and not backing up anyone else. My external drive died. I'm looking for a more elegant/seamless solution.
- Large external drive on my iMac and somehow partition/share it to the other Macs?
- A wireless NAS device?
- A wired NAS device?
- I looked at the Time Capsule, but I don't want/need a new router necessarily, and I don't know what the access control features are like.

Any advice appreciated!

I should add, that some years ago I had a Buffalo Linkstation for a while on my network when it was PC only. It was 'ok' to use, but not as dead simple as I wanted.
Later, I added a HP495 Windows Home Server, it was interesting, but again not hands-free. Seemed like I always had to reestablish the shared drive connection and then force a backup vs having it run seemlessly in the background.

I just picked up one of the still in stock last gen 3TB Time Capsules at Fry's for $249.
Can't get any more seamless than a TC and why I'm willing to pay a little more for it.
My first gen TC has lasted over 6 years. (The one that was suppose to die after 18 months according to all the press reports at the time.)

If you're doing all the control at your current router, doesn't matter what controls the TC has - your existing router continues doing it's job as the DHCP server and set the TC up in bridge mode.

(I had one of those HP Win Home Server units also - biggest pitb computing device I've ever owned in my life - I was actually glad when it died.)

Synology devices do Time Machine pretty well, and will also offer iSCSI options for your Windows machines. Personally I have found that the Linkstation works, but the wireless is way too slow. I would recommend whatever solution you decide on to make sure it is wired. The initial Time Machine backup over wireless can be painfully slow.

The backups to my Synology have been flawless, and the Windows backups have worked perfectly as well.

There are many options out there at varying prices. Entry level Synology will put you in the $500-$600 range depending on hard drives.

Of course, Time Capsule is the easiest!

^^^ Synology does make some nice devices.

I had looked at the Synology frames and they seemed very nice, but I wondered if they were overkill for what I was looking to do. I don't have any movies to stream or wiki's to host. I do have iTunes, but we've never needed to centralize and stream from it.

I looked at Fry's and the one near my brother doesn't have any prior version TCs in stock...they don't sell them online. I'm sure I could still find one somewhere. I hadn't considered it set up as a bridge...that would be a simple solution.

I also peeked at the WD My Cloud and Seagate solution...seemed simple enough, but not great online reviews if they are to be believed.