Check XRefs for 'Attach' or 'Overlay'

I need a program to run a check on so many files based on some file name conditions.

For Eg.

All the floorplans will be named with *xpl* format. (gfxpl01, ffxpl02 sfxpl01 etc...)

(Infact 'xpl' is common in all floor plans)

All the elevations will be named with *xel* format. (Exel001, Ixel002, Exel003 etc...)

(Infact 'xel' is common in all elevations)

Ceiling plans in *xcl* format. (Infact 'xcl' is common in all ceiling plans)

Now my concern is;

The lisp should identify the active drawing from its name, if it is an elevation file. then check all the XRefs by name, for '*xpl*' (floor plans) format and '*xcl*' format. Check if they are 'Overlay'. If they are 'Attachment's, change it to 'Overlay'.

is there any way to do this?