Same External Number Range for two Customer Account Group

Hello Experts,

There is a scenario in number range ie: -

I have two customer account group ZSEP (Sales Employee) and ZVAN (Van Man) this are two account group but the person is one only.

Suppose Henry is a Sales Employee of the company and he is a VanMan who is doing sales on VAN.

Now the scenario is that, for this two Customer acc. Group ZSEP and ZVAN we want one External Customer code, ie: same number range for two different customer acc. Group.

I tried it by assigning same external number range via XDN1 but it is not picking the same customer code for two different cust acc group., showing the error of ”Customer already exist in sales area”

I have searched in the forum also but didn't have the relevant information.

Kindly suggest me how can I give the same external number range to two different Cust. Acc. Group.

Regards

Parag Pandya