[OE-core] Multiple systemd service packages for single recipe

[Yevhen Kyriukha]

How can I generate multiple systemd service packages for single recipe?

I'm building connman with VPN support and I want to have
connman-systemd and connman-vpn-systemd packages.
I'm using following syntax for connman recipe but no
"connman-vpn-systemd" is generated:

SYSTEMD_PACKAGES += "${PN}-systemd ${PN}-vpn-systemd"
SYSTEMD_SERVICE_${PN}-systemd = "connman.service"
SYSTEMD_SERVICE_${PN}-vpn-systemd = "connman-vpn.service"
FILES_${PN}-vpn-systemd +=
"${datadir}/dbus-1/system-services/net.connman.vpn.service"