grouping number and string data types into one dimension

[bharti_joseph]

I have two different data types in a dimension , number and range under the dimension  for employee size:

e.g. 1,2,3,4…..and  2-7,8-19,20-39,40-99,100+   

I need to create a custom dimension for employee size ranges:

1

2-7

8-19

20-39

40-99

100+

and unknown. 

How can this be done either in custom dimension or in LookML?