Welcome to EpoS Wizard!
PC-Based Multi-site solution
A traditional Back Office isn't really a possibility. The 'sites' are all going to be contained within the same building (as is the 'Master') and running on decent cabling, switches etc.
We have actually been looking very closely at SharpPOS, running the ECR Manager (I believe) on the 'Master' as we need the loyalty and customer details to be updated live across the entire system.
If it's hospitality then you have the option for Maître D. Not sure if it's offered in your area but I would assume its global.
PC based, can set up your own screens, you have back office functionality...
Yes Maitre'D will do exactly what you want by the sounds of it.
If you want any inofrmation then get in touch.