How to set the remote host to a domain name with dynamic IP in *swan client?

Question

I am now setting a vpn client for my university's own L2TP/IPSec VPN network, using both openswan, libreswan and strongswan (for different distros).

Here is the problem:

The remote site (VPN server) is a domain name (say xxx.com) with multiple IP addresses (say 123.123.123.100-123.123.123.103).

In this case, how should I set the conn part?

I have tried something like:

conn university
    ...
    left=%defaultroute
    right=xxx.com
    ...
    auto=route

Which seems not working, since when *swan start, it parses xxx.com and setup the route by the IP returned by the DNS request (say 123.123.123.100). Then when I make a connection to xxx.com, it may parse the domain again and get a different IP (say 123.123.123.101), and the connection will not go through *swan.

I have also tried the rightsubnet option, but I don't know what should be the right option. If I just use %any, *swan will give some error like No route to destination (something like that, cannot remember) and refuse to add the conn.

Now my workaround is:

conn university0
    right=123.123.123.100
    also=university
    auto=route

conn university1
    right=123.123.123.101
    also=university
    auto=route

conn university2
    right=123.123.123.102
    also=university
    auto=route

conn university3
    right=123.123.123.103
    also=university
    auto=route

conn university4
    right=123.123.123.104
    also=university
    auto=route

conn university
    left=%defaultroute
    ...

...which works, but seems ugly and non-scalable.

In the past, when I use racoon, I can use the setkey command to modify the SPD directly, so I can set policies for the corresponding IPs directly.

I think this case is common and there will be a solution designed for this case in *swan. Anyone can help?