额 刚从手册里找到啦
route_zrt_group performs detail routing of the clock nets.
You can also perform detail routing of the clock nets as a standalone process, using the
route_zrt_group -all_clock_nets -reuse_existing_global_route true
command.
To prevent routing of the clock nets, use the -no_clock_route option of the clock_opt
command
这是手册里的。而route_group应该是global route吧,请大神们指正