Hi Baiquan,
Definitely what you ask is possible. I would do the following model;
1- Create entities for each excel file and import excel files through these entities. Lets say import entities.
2- Create a final entity (whole )
3- After importing all the excel files, it is time to play work on this data by using ket attributes (the one element related to the other entity)
4- Finally, Copy all the attributes to the final the whole entity.
Shortly, Import Entity A, Entity B, Entity C
By using the key attibute from Entity A finds the related data from Entity B and same for B to C.
Create Object (Entity ABC- Whole dataset) by using linked objects from entity A, B and C.
I hope it works for you.
Ferhat