Yes, you can. For phones that come with a hardware Redial Button () you can do the following:
This will configure the Redial Button to press as well the OK key, thus dialling the first number in the dialled numbers list.
By pressing that key the phone will immediately redial the last dialled number.
For phones that do not come with a hardware Redial Button, it is possible to re-program for example the OK (check) button or any other button with the above action URL. If the web user interface does not have the "Action URL" option (for example for the OK button), you can as well use a setting file to configure the phone and set the following:
<idle_ok_key_action perm="">url http://127.0.0.1/command.htm?key=F_REDIAL;F_OK</idle_ok_key_action>