It can be splitted! The a-record in the registration of the domain determines where the mail goes and another record determines where the internet goes. I have a domain, axj.dk, where I run a web-site on my Synology, but the mail is sent to me via another company while the ISP is a third company (with another mail-address!).
DS509+ 4*1TB Raid+1TB DSM 4.0-2219. Logitech BOOM+Duet 7.6.1, WebCam: Linksys WVC54GCA + TrendNet TV-IP121
DS212+ 1TB & D-Link DIR-685, HP C7280, Dell 3100cn. iPad3, Programming Pascal, Clarion 5.5, html/php. http://axj.dk