[SR-Users] How to chain proxies with Route header and loose_route()

Assuming there are several proxies that have to be hopped sequentially to deliver the request and the order is determined dynamically (!), how can one achieve that behaviour in Kamailio? My understanding was that Route header is used for that - it allows to keep R-URI intact but still route the egress message elsewhere. Documentation of the loose_route() from RR module seems to confirm that. But the catch is that loose_route() will not pick up any Route header that I might add in the config via append_hf() due to the delayed lump processing (as explained in https://sourceforge.net/p/openser/bugs/277/#5f42). Thanks in advance for any help or ideas. Regards, Ivan