Happy New year Pratima!

I trust all is well with you and hope you could assist me with the following situation.

I created a custom object (Parameter - child object to account). Let assume that this object has 5 record types (purchasing;licensing; remarketing; etc...). I would like to have a lookup field auto populate on a case object when i select a specific case record type (same name as in custom object) instead of having the user selecting a record.

For example:

Customer object Fields(Parameter):

Field#1 - Record type Name:Purchasing (Record#1) or Licensing(Record#2)

Field#2 - Master-details field - Account Name (): Canada

Field#3 - Text Field - Purchasing Details (Record#1) or Licensing Details(Record#2)

Standard Object (Case)

Account Name (Master-Detail field)

Record type Name: Purchasing

Lookup field: Parameter: (this field will be empty; but it'll show all records related to the same account name(custom object). I'd like it to auto populate Purchasing records only - Custom Object)

Thank you in advance for your assistance.