How to add solution as a text file into VSTS Source Control System?

It seems that in VSTS solution file and project file has a strong relations. In some situations, I have to use several solution files, and project files contained in these solutions file are overlapped. for example :

Solution A : proj 1, proj 2, proj 3;
Solution B : proj 2, proj 3, proj 4;
Solution C : proj 1, proj 2, proj 4;

Solution A, B, C files may in the same folder or in different folders. If I add all these solution files to VSTS source control, is there any conflect If so, could I just add the project files seperately and add solution file as text files

Thanks!