jails jail configuration ip4.addr parameter clarification

[bcrashkopf]

According to the jail() manual:

It is only possible to start multiple jails with the same IP address if none of the jails has more than this single overlapping IP address assigned to itself.

Does this mean that only one IP address can be shared amongst jails, or that jails sharing an IP address can only have a single address?
It seems to be the latter:

jail1 {
        ip4.addr="lo1|127.1.1.2";
        ip4.addr+="10.10.10.16";
}
jail2 {
        ip4.addr="lo1|127.1.1.3";
        ip4.addr+="10.10.10.16";
}

When starting the second jail it fails with the error "IPv4 addresses clash"

Can I share an IP between jails and still assign other IPs?