Combine series of data from different excel files

Hello all

Is there any chance of combining different data on a chart?

I have this series:

=SERIES([sample.xlsx]Assid.!$B$33;[sample.xlsx]Assid.!$C$3:$Q$3;[sample.xlsx]Assid.!$C$33:$Q$33;1)

I am calling the series from a different excel file and all I wanna do now is to combine more data into that series and show on a chart. Help me out here

Thank you for your help in advance.