Not with PROC Export and likely not with any Export data widget or task.
ODS and Proc print:
ods excel file="x:\example.xlsx" options(sheet_interval='PROC');
proc print data=sashelp.class noobs;
run;
proc print data=sashelp.cars noobs;
run;
ods excel close;
There are other valid sheet_interval options but this is likely to work for this sort of thing IF the data sets are small enough to fit on a single sheet.