VB5 - VB6 What's going on here?

I have two VB projects. I wrote both of them in VB6. By themselves, they work perfectly. Now I combine the two projects together and create a Group.vbg file. When I click on the Group.vbg file the first error I get is "Retained" is an invalid keyword.......Project1.vbp could not be loaded.
When I look inside the vbp file I see the Retained=0 keyword. It wasn't there before. So, I remove itand resave the vbp file. Now I click on Group.vbg again and again this error: "Retained" is an invalid keyword.......Project2.vbp could not be loaded. This time it's Project2.vbp. So, I edit Project2.vbp and remove the Retained keyword, which was not there before just like Project1.vbp. Now I click on the Group.vbg file again and this time it loades up the two projects but noe when I go to run it I get invalid errors on certain functions: Split, InStr, and others. These are valid in VB6 but they are not valid in VB5. I also noticed after the group project was loaded the the version of VB is not VB 6.0 but rather it is VB 5.0.

Since both Project1 and Project2 were written in VB6 the only thing I can conclude is that when they are combined as a group something changes and the system thinks the group is a VB5 group project. I can not get around this.

Can anyone tell me why this is happening?