Sequential Transfer()s in script fail and segfault

[racingmars]

After connecting to an MVS mainframe with c3270, at the TSO prompt, I press the escape sequence and type Source(backup). The file backup has lines such as:

Transfer(Direction=receive,HostFile=file1,LocalFile=...)
Transfer(Direction=receive,HostFile=file2,LocalFile=...)
...more Transfer() lines...

After the first line executes, the second line immediately executes, and c3270 gives an error message that a transfer is already in progress, then segfaults.

I have put a Wait(5,Seconds) line between each Transfer() line, which makes the script take longer than it needs to (the files transfer more quickly than 5 seconds, but I feel like I should build in a safety margin). The other types of Wait()s don't seem to wait for the file transfer to finish.

Is there a way to explicitly wait just long enough for the file transfer to complete? Since c3270 knows that a file transfer is already in progress when it reports the error when running the second line, it seems like it would have a Wait() that waits until no transfer is in progress.