Merge the same Criteria cell data

The author of the unit this year has implemented the National Computer Application grade examination, according to the promotion job level different, examinee may choose 2 to 4 modules examination. Each examinee has the unique file number, the same examination qualified 1 and above module, obtains 1 Qualifications certificate, the certificate marking examinee qualified module.

If the candidate Liu XX qualified 1, there are 1 certificate, the examinee Wang xx qualified 3 families, also obtained a Certificate of conformity, certificate showed the Qualified 3 modules (Figure 1). In order to facilitate inquiries and to facilitate candidates to receive the card signature, the same file number of candidates in Figure 1 of the qualified modules to be merged, the module with "/" separated (Figure 2), then how to achieve this effect? Because the same file number has 2, 3, and 4 three cases, the number of modules to be merged is not fixed, and an array formula is needed to resolve such problems.

Figure 1 Three modules of the same file number in an Excel table

Figure 2 Merging excle the same file