[Armistead]

I'm not at a PC with SH4 files to refresh myself, but as I recall, if you want a generic to replace a certain ship, don't include the class line, just enter the type number.

For instance, if a certain unit in the group, say a merchant, you'll see a line like

Class= {actual type,}

Delete the class line, then it will pick a generic. Then you'll see the a line,

Type=101

Just enter the correct number for type, which I think is 101 for tankers, 102 for merchants, 103, for PS, etc. but you can find and compare another file to get correct type numbers.

Hope that makes sense. Delete Class line, enter correct Type, adjust other values as needed, cargo, crew rating, if you so desire.