I have the following tables in my model$-$driven app solution.

SMART Audit Customers

SMART Audit Auditors

SMART Audit Customer Equipments

SMART Audit Equipment Lines

SMART Audit Recommendations

SMART Audit Visits

User

Vendors V$2($mserp$)$

Customers V$3($mserp$)$

Customer postal address $($mserp$)$

Assets entity view V$3($mserp$)$

In SMART Audit Customers $-$ we have relationships $-$ Account Manager $($Lookup to SMART Audit Auditors many to one$),$ Customer $($Lookup to SMART Audit Visits One to many$),$ Customer $($Lookup to SMART Audit Customer Equipments one to many$),$ Customer $($Lookup to Customers V$3($mserp$)$ many to one$)$

In SMART Audit Visits $-$ we have relationships $-$ Auditor $($Lookup to SMART Audit Auditors many to one$),$ Customer $($Lookup to SMART Audit Customers many to one$),$ Visit $($Lookup to SMART Audit Equipment Lines One to many$)$

In SMART Audit Customer Equipments $-$ Customer $($lookup to SMART Audit Customers many to one$),$ Customer Equipment $($Lookup to SMART Audit Equipment Lines one to many$),$ Serial No $($lookup to Assets entity view V$3($mserp$)$ many to one$).$

We need to use Javascript to filter the lookup$($Serial No$)$ based on the customer.

We need to get the customer from Visits related to Equipment Line $($Audit Customers$).$

Pre search to Filter Customer Equipment lookup $($SerailNo$)$ based on retrieved customer value $($Audit Customers$).$