Lisp to combine 2 separate blocks into 1 new block based of insert point position

Hi,

im looking for a lisp that finds any blocks that are in the same position based of insertion point and "combines these two blocks to create a new one with the names attached to them.

for example say i has a line y co-ordinate starting at 0 ending at 5000.

if two blocks where located at the midpoint 2500 (block a.dwg + block b.dwg) but these are 2 separate blocks. is there a way for these blocks to be combined into 1 new block called block a + block b.dwg? likewise if there where 3? block a + block b + block c.dwg?

Lisp to combine 2 separate blocks into 1 new block