import re
rx = r"\b[A-Z](?=([&.]?))(?:\1[A-Z])+\b"
s = "My name is STEVE. My friend works at (I.A.). Indian Army(IA). B&W also B&&W Also I...A"
print( [x.group() for x in re.finditer(rx, s)] )
aW1wb3J0IHJlCnJ4ID0gciJcYltBLVpdKD89KFsmLl0/KSkoPzpcMVtBLVpdKStcYiIKcyA9ICJNeSBuYW1lIGlzIFNURVZFLiBNeSBmcmllbmQgd29ya3MgYXQgKEkuQS4pLiBJbmRpYW4gQXJteShJQSkuIEImVyBhbHNvIEImJlcgQWxzbyBJLi4uQSIKcHJpbnQoIFt4Lmdyb3VwKCkgZm9yIHggaW4gcmUuZmluZGl0ZXIocngsIHMpXSAp