How to dynamically configure an US-IP as exit node?

["Ben Stover" <bxstover@xxxxxxxxxxx>]

Ok, as well documented I can specify write into the torrc file

StrictExitNodes 1
exitnodes aaa, bbb, ccc, dddd

where aaa, bbb, ccc and ddd are Tor nodes located in the US.

The problem with this is that the nodes aaa, bbb, ccc, ddd are not constant over a period of time.
Nodes become removed or inactive. Furthermore other nodes are still alive but other nodes have a better bandwith 
and throughput.

So is there another way to specify just the country of the exit node and let Tor choose automatically a suitable
exit node from this country?

Alternatively Is there a way to dynamically update the list in torrc file?
I could imagine that there is a tool which searches automatically at startup of local Tor for nodes in a target country
and updates - if neceesary - the old list in torrc.

Is this possible somehow?

Thx
Ben