[R] launching two RGUI computations from two different Excel workbooks

[sowhat2 at o2.pl]

Hello,

I have the following problem:

I have excel workbooks connected with R through RExcel package. Data are being loaded from excel, then they are processed in R and then the results are being put in excel. Everything works fine, except the fact that I can't launch two or more excel workbooks (and two or more R servers in the background) at the same time. 
I have to wait until one computation is finished and then launch another one. It would be much easier and quicker for me to launch two or more computations at the same time. Is this possible to launch two different R servers from Excel?

Regards,

Wojciech Turski